Microsoft Service Health Updates for Microsoft Outages MO1550821 and EX1550543

Microsoft users started experiencing service disruptions and outages, impacting Outlook, Exchange Online, and Microsoft Teams, followed by additional Microsoft 365 services on the morning of November 12, 2026. 

If you're interested in accessing Microsoft's updates, keep scrolling. Please note, we're updating this post, but not in real time; therefore, updates may not reflect Microsoft's most recent information. 

For an overview, here is The Timeline & Progression of the Microsoft Outage on November 12, 2026. 

The outage has been acknowledged by Microsoft on X through their @MSFT365Status feed, but users are also experiencing issues accessing the Microsoft 365 admin center and status.cloud.microsoft.  

ENow Software's Microsoft 365 Monitoring tool provides access to service health notifications directly through its Service Dashboard, which brings together @MSFT365Status X feed for updates alongside Microsoft Service Health Notifications for exactly this scenario.

For those without access to Microsoft's direct updates at this time, here is what we see.

Microsoft Service Health Updates for MO1550821

MO1550821 - Users may be unable to connect to multiple Microsoft 365 services

Impacting: Microsoft 365 suite; Estimated start time: Thursday, November 12, 2026 10:26 AM

Skip to Latest Update Included

11/12/2026 10:27:35 AM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Potentially impacted services include:
- Exchange Online
- Microsoft Teams
- SharePoint Online
- Microsoft Copilot 365
- Microsoft Defender XDR

Current status: We’re investigating an issue impacting multiple Microsoft 365 services and we've determined the affected infrastructure is experiencing elevated load across multiple regions, which is likely contributing to the connectivity errors. We're restarting and repairing impacted portions of this infrastructure to restore capacity, and reviewing an unexpected increase in a specific type of service traffic to determine whether it's contributing to the elevated load. In parallel, we're evaluating options to redirect traffic to alternate infrastructure to expedite relief.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Thursday, November 12, 2026, at 8:30 PM UTC

11/12/2026 10:58:10 AM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Potentially impacted services include:
- Exchange Online
- Microsoft Teams
- SharePoint Online
- Microsoft Copilot 365
- Microsoft Defender XDR

Current status: We've completed redistributing connection traffic across our worldwide infrastructure, and we're moving additional traffic off the affected infrastructure to further reduce load. We're also restarting affected servers to return them to service. In parallel, we're investigating whether the elevated traffic reflects a genuine increase in requests or a shift in how traffic is being routed across our infrastructure.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Thursday, November 12, 2026, at 9:00 PM UTC

11/12/2026 11:30:15 AM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Potentially impacted services include:
- Exchange Online
- Microsoft Teams
- SharePoint Online
- Microsoft Copilot 365
- Microsoft Defender XDR

Current status: We're aggressively pursuing all pathways to reduce impact. As a precaution, we've paused all deployments and configuration changes while we review recent changes for any correlation to this event. We've determined that the elevated load isn't driven by an overall increase in traffic, but by a large number of servers being unexpectedly unavailable, which is shifting load onto the remaining infrastructure. We're investigating what's causing these servers to become unavailable while we work to safely return them to service.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Thursday, November 12, 2026, at 10:00 PM UTC

11/12/2026 11:43:19 AM 

We've identified that affected servers are failing automated health checks, which is causing them to become unavailable, and this may be related to a recent change to a component involved in processing those checks. We're testing a configuration change on a subset of affected infrastructure to address this and, if successful, will apply it more broadly. In parallel, we've initiated a restart of all affected servers and are validating whether they're successfully returning to service.

This quick update is designed to give the latest information on this issue.

Next update by: Thursday, November 12, 2026, at 10:00 PM UTC

11/12/2026 11:58:41 AM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Potentially impacted services include:
- Exchange Online
- Microsoft Teams
- SharePoint Online
- Microsoft Copilot 365
- Microsoft Defender XDR
- Microsoft Planner
- Microsoft To Do
- Microsoft Purview: Multiple Purview services including Authorization, Auto Labelling, Data Loss Prevention (DLP), Communication Compliance, and Data Classification are impacted.

Current status: While we haven't identified any recent changes that correlate with the start of impact, our investigation indicates the failed health checks may originate from a specific component on the affected servers that's responsible for processing them. We're deploying a targeted change to bypass this component on a subset of servers to validate whether this restores availability, and we've taken steps to prevent additional servers from being removed from service while we work to return the affected servers to service. We're also investigating why affected servers are experiencing elevated processor usage while handling requests.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Thursday, November 12, 2026, at 9:30 PM UTC

11/12/2026 12:38:42 PM 

While validating the targeted change, we found that many of the affected servers have become unresponsive, which is preventing us from confirming whether the change is effective. We're restarting these servers so they can come back online with the change in place, and we're applying the same approach to additional affected portions of our infrastructure to validate the results more broadly.

Next update by: Thursday, November 12, 2026, at 9:30 PM UTC

This quick update is designed to give the latest information on this issue.

11/12/2026 12:57:05 PM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: More info: Potentially impacted services include:
- Exchange Online
- Microsoft Teams
- SharePoint Online
- Microsoft Copilot 365
- Microsoft Defender XDR
- Microsoft Planner
- Microsoft To Do
- Microsoft Intune
- Microsoft Defender for Office 365
- Microsoft Purview: Multiple Purview services including Authorization, Auto Labelling, Data Loss Prevention (DLP), Communication Compliance, and Data Classification are impacted.
- Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.

Current status: We've validated an alternative health check method on a subset of affected infrastructure, which allowed the servers in that subset to successfully return to service, and we're now applying this change more broadly. We're also preparing an automated recovery process to continually detect and restart unresponsive servers, to help keep them in service while this change progresses. Additionally, our review of recent changes has identified a small number of configuration updates that we're investigating as potential contributors to the issue.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Thursday, November 12, 2026, at 10:30 PM UTC

11/12/2026 1:31:54 PM 

We're continuing to work through restarting and validating the affected servers to safely return them to service, and we're exploring opportunities to expedite this process. In parallel, we're assessing whether reverting the small number of recent configuration updates we identified could help accelerate recovery.

Next update by: Thursday, November 12, 2026, at 10:30 PM UTC

This quick update is designed to give the latest information on this issue.

11/12/2026 2:03:00 PM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Potentially impacted services include:
- Exchange Online
- Microsoft Teams
- SharePoint Online
- Microsoft Copilot 365
- Microsoft Defender XDR
- Microsoft Planner
- Microsoft To Do
- Microsoft Intune
- Microsoft Defender for Office 365
- Microsoft Purview: Multiple Purview services including Authorization, Auto Labelling, Data Loss Prevention (DLP), Communication Compliance, and Data Classification are impacted.
- Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.
- Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory.
- Universal Print: Users may encounter errors submitting print jobs or using admin features.

Current status: We’re continuing to pursue all available pathways to restore service, as our actions taken thus far have not provided the anticipated relief. Our investigation has found that a core process on the affected servers is becoming overwhelmed, which causes the servers to stop responding and contributes to the capacity loss.

To validate a potential recovery approach, we're fully isolating a portion of our service infrastructure, restarting the affected components, and gradually reintroducing traffic to confirm our services remain stable before applying this approach more broadly. We're also analyzing traffic patterns across our entire service infrastructure and evaluating whether isolating traffic within each region may allow affected regions to recover independently.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Thursday, November 12, 2026, at 11:30 PM UTC

11/12/2026 2:03:00 PM

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Potentially impacted services include:
- Exchange Online
- Microsoft Teams
- SharePoint Online
- Microsoft Copilot 365
- Microsoft Defender XDR
- Microsoft Planner
- Microsoft To Do
- Microsoft Intune
- Microsoft Defender for Office 365
- Microsoft Purview: Multiple Purview services including Authorization, Auto Labelling, Data Loss Prevention (DLP), Communication Compliance, and Data Classification are impacted.
- Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.
- Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory.
- Universal Print: Users may encounter errors submitting print jobs or using admin features.

Current status: We’re continuing to pursue all available pathways to restore service, as our actions taken thus far have not provided the anticipated relief. Our investigation has found that a core process on the affected servers is becoming overwhelmed, which causes the servers to stop responding and contributes to the capacity loss.

To validate a potential recovery approach, we're fully isolating a portion of our service infrastructure, restarting the affected components, and gradually reintroducing traffic to confirm our services remain stable before applying this approach more broadly. We're also analyzing traffic patterns across our entire service infrastructure and evaluating whether isolating traffic within each region may allow affected regions to recover independently.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Thursday, November 12, 2026, at 11:30 PM UTC

11/12/2026 2:58:28 PM

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Potentially impacted services include:
- Exchange Online
- Microsoft Teams
- SharePoint Online
- Microsoft Copilot 365
- Microsoft Defender XDR
- Microsoft Planner
- Microsoft To Do
- Microsoft Intune
- Microsoft Defender for Office 365
- Microsoft Purview: Multiple Purview services including Authorization, Auto Labelling, Data Loss Prevention (DLP), Communication Compliance, and Data Classification are impacted.
- Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.
- Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory.
- Universal Print: Users may encounter errors submitting print jobs or using admin features.

Current status: We've begun returning a portion of the affected servers to service, and they're remaining stable so far. We’ve also shifted traffic and connections to alternative pathways wherever possible and have observed limited recovery in some regions.

We've streamlined our recovery process to expedite returning the remaining affected servers to service. To further support recovery, we're implementing protective traffic management measures in a specific location to reduce load on the affected infrastructure, and we'll expand these measures to additional locations if we observe positive results. As capacity is restored, users may experience a gradual recovery as their clients reconnect to the service.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Friday, November 13, 2026, at 12:30 AM UTC

11/12/2026 4:00:13 PM

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Features of the Microsoft 365 services below that interact with Exchange Online and email services are impacted. Elements of those services that do not depend on interaction with Exchange Online remain functional.

• Exchange Online: Users may be unable to access their mailbox using Outlook on the web, Outlook desktop (MAPI), Exchange ActiveSync (EAS), or REST-based connections, and email delivery may be delayed.

• Microsoft Teams: Scenarios that depend on Exchange Online, including calendar, meeting scheduling, and creating chats for organizations using Information Barriers, may fail. Core messaging and online meetings remain largely functional.

• SharePoint Online: Features that depend on Exchange Online may be impacted. Accessing files stored directly in SharePoint Online remains functional.

• Microsoft Copilot 365: Users may be unable to load Copilot Chat or receive responses in the web and desktop apps, and Copilot experiences may be unable to access work data such as email, calendar, and files.

• Microsoft Defender XDR: Users may be unable to load Microsoft Defender portal pages or solution tabs.

• Microsoft Planner: Users are experiencing Plan and Task operation reliability issues.

• Microsoft To Do: The app may not load, and users may see operation failures.

• Microsoft Intune

• Microsoft Defender for Office 365: Safe Links may be unable to verify URLs, which may impact users clicking links in Outlook and Teams.

• Microsoft Purview: Multiple Purview services including Authorization, auto-labeling, Data Loss Prevention (DLP), Communication Compliance, and Data Classification are impacted, and users may be unable to load Microsoft Purview portal pages.

• Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.

• Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory are affected. Users may encounter page load and content not loading failures.

• Universal Print: Users may encounter errors submitting print jobs or using admin features.

• Windows 365: Customers who have configured their tenant and Cloud PCs to use Microsoft Purview Customer Key for Windows 365 Cloud PCs may have users who are unable to connect to their Cloud PCs.

• Microsoft 365 admin center: Admins may be unable to load some admin center pages.

• Microsoft Graph: API requests that access Exchange Online data, such as mail, calendar, and contacts, may time out.

• Microsoft 365 apps: Users may be unable to view their recently used files.
• Microsoft 365 Education: Features including Assignments, Reading Progress, and Speaker Progress may be impacted.

Current status: While the servers we've returned to service initially remain healthy, we've observed that they can become unresponsive again once they begin receiving traffic. We're analyzing diagnostic data from these servers with our networking and platform experts to determine what's triggering this behavior.

Building on the protective traffic management measures we've implemented, we're also temporarily limiting which types of traffic can reach the affected infrastructure in specific locations. This will help us determine whether a particular type of request is contributing to the impact and allow us to restore service incrementally. Additionally, we're rebuilding a subset of affected servers using a previous software configuration to validate whether this prevents them from becoming unresponsive, and we'll expand this approach to additional servers if we observe positive results.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Friday, November 13, 2026, at 1:30 AM UTC

11/12/2026 4:45:16 PM

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Features of the Microsoft 365 services below that interact with Exchange Online and email services are impacted. Elements of those services that do not depend on interaction with Exchange Online remain functional.

• Exchange Online: Users may be unable to access their mailbox using Outlook on the web, Outlook desktop (MAPI), Exchange ActiveSync (EAS), or REST-based connections, and email delivery may be delayed.

• Microsoft 365 admin center: Admins may be unable to load some admin center pages.

• Microsoft 365 apps: Users may be unable to view their recently used files.

• Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory are affected.

• Microsoft 365 Education: Features including Assignments, Reading Progress, and Speaker Progress may be impacted.

• Microsoft Copilot 365: Users may be unable to load Copilot Chat or receive responses in the web and desktop apps, and Copilot experiences may be unable to access work data such as email, calendar, and files.

• Microsoft Defender for Office 365: Safe Links may be unable to verify URLs, which may impact users clicking links in Outlook and Teams.

• Microsoft Defender XDR: Users may be unable to load Microsoft Defender portal pages or solution tabs.

• Microsoft Fabric: Users may encounter failures when exporting reports with sensitivity labels to PDF or PowerPoint, or when updating artifacts with sensitivity labels.

• Microsoft Graph: API requests that access Exchange Online data, such as mail, calendar, and contacts, may time out.

• Microsoft Intune

• Microsoft Planner: Users are experiencing Plan and Task operation reliability issues.

• Microsoft Purview: Multiple Purview services including Authorization, auto-labeling, Data Loss Prevention (DLP), Communication Compliance, and Data Classification are impacted, and users may be unable to load Microsoft Purview portal pages.

• Microsoft Teams: Scenarios that depend on Exchange Online, including calendar, meeting scheduling, and creating chats for organizations using Information Barriers, may fail. Core messaging and online meetings remain largely functional.

• Microsoft To Do: The app may not load, and users may see operation failures.

• Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.

• SharePoint Online: Features that depend on Exchange Online may be impacted. Accessing files stored directly in SharePoint Online remains functional.

• Universal Print: Users may encounter errors submitting print jobs or using admin features.

• Windows 365: Customers who have configured their tenant and Cloud PCs to use Microsoft Purview Customer Key for Windows 365 Cloud PCs may have users who are unable to connect to their Cloud PCs.

Current status: We've reviewed known impact scenarios and have revised the list of impact services and features, which can be viewed in the "more info" section of this communication.

We're continuing our work to isolate the issue affecting server availability, as well as other workstreams.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Friday, November 13, 2026, at 1:30 AM UTC

11/12/2026 5:12:07 PM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Features of the Microsoft 365 services below that interact with Exchange Online and email services are impacted. Elements of those services that do not depend on interaction with Exchange Online remain functional.

- Exchange Online: Users may be unable to access their mailbox using Outlook on the web, Outlook desktop (MAPI), Exchange ActiveSync (EAS), or REST-based connections, and email delivery may be delayed.
- Microsoft 365 admin center: Admins may be unable to load some admin center pages.
- Microsoft 365 apps: Users may be unable to view their recently used files.
- Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory are affected.
- Microsoft 365 Education: Features including Assignments, Reading Progress, and Speaker Progress may be impacted.
- Microsoft Copilot 365: Users may be unable to load Copilot Chat or receive responses in the web and desktop apps, and Copilot experiences may be unable to access work data such as email, calendar, and files.
- Microsoft Defender for Office 365: Safe Links may be unable to verify URLs, which may impact users clicking links in Outlook and Teams.
- Microsoft Defender XDR: Users may be unable to load Microsoft Defender portal pages or solution tabs.
- Microsoft Fabric: Users may encounter failures when exporting reports with sensitivity labels to PDF or PowerPoint, or when updating artifacts with sensitivity labels.
- Microsoft Graph: API requests that access Exchange Online data, such as mail, calendar, and contacts, may time out.
- Microsoft Intune
- Microsoft Planner: Users are experiencing Plan and Task operation reliability issues.
- Microsoft Purview: Multiple Purview services including Authorization, auto-labeling, Data Loss Prevention (DLP), Communication Compliance, and Data Classification are impacted, and users may be unable to load Microsoft Purview portal pages.
- Microsoft Teams: Scenarios that depend on Exchange Online, including calendar, meeting scheduling, and creating chats for organizations using Information Barriers, may fail. Core messaging and online meetings remain largely functional.
- Microsoft To Do: The app may not load, and users may see operation failures.
- Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.
- SharePoint Online: Features that depend on Exchange Online may be impacted. Accessing files stored directly in SharePoint Online remains functional.
- Universal Print: Users may encounter errors submitting print jobs or using admin features.
- Windows 365: Customers who have configured their tenant and Cloud PCs to use Microsoft Purview Customer Key for Windows 365 Cloud PCs may have users who are unable to connect to their Cloud PCs.

Current status: Our investigation has found that a process on the affected servers responsible for establishing secure connections becomes overwhelmed, causing the servers to stop processing requests. We're preparing a configuration change to address this behavior that can be applied across all affected servers, and we're validating it on a subset of servers before applying it more broadly alongside restarts of the affected infrastructure. In parallel, we've begun reverting a recent network configuration change that correlates with the start of impact and are monitoring to determine whether this contributes to recovery.

The temporary traffic limitations we previously described are now in effect in specific locations. We're monitoring the affected servers in those locations to confirm whether they remain stable while handling a narrower set of connections, after which we'll gradually reintroduce additional traffic.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Friday, November 13, 2026, at 2:30 AM UTC

11/12/2026 5:48:17 PM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Features of the Microsoft 365 services below that interact with Exchange Online and email services are impacted. Elements of those services that do not depend on interaction with Exchange Online remain functional.

- Exchange Online: Users may be unable to access their mailbox using Outlook on the web, Outlook desktop (MAPI), Exchange ActiveSync (EAS), or REST-based connections, and email delivery may be delayed.
- Microsoft 365 admin center: Admins may be unable to load some admin center pages.
- Microsoft 365 apps: Users may be unable to view their recently used files.
- Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory are affected.
- Microsoft 365 Education: Features including Assignments, Reading Progress, and Speaker Progress may be impacted.
- Microsoft Copilot 365: Users may be unable to load Copilot Chat or receive responses in the web and desktop apps, and Copilot experiences may be unable to access work data such as email, calendar, and files.
- Microsoft Defender for Office 365: Safe Links may be unable to verify URLs, which may impact users clicking links in Outlook and Teams.
- Microsoft Defender XDR: Users may be unable to load Microsoft Defender portal pages or solution tabs.
- Microsoft Fabric: Users may encounter failures when exporting reports with sensitivity labels to PDF or PowerPoint, when updating artifacts with sensitivity labels, or opening pbix with sensitivity label in Power BI Desktop. As a workaround, users can remove the sensitivity label from the affected item to complete the operation, if their organization's data protection policies allow it.
- Microsoft Graph: API requests that access Exchange Online data, such as mail, calendar, and contacts, may time out.
- Microsoft Intune
- Microsoft Planner: Users are experiencing Plan and Task operation reliability issues.
- Microsoft Purview: Multiple Purview services including Authorization, auto-labeling, Data Loss Prevention (DLP), Communication Compliance, and Data Classification are impacted, and users may be unable to load Microsoft Purview portal pages.
- Microsoft Teams: Scenarios that depend on Exchange Online, including calendar, meeting scheduling, and creating chats for organizations using Information Barriers, may fail. Core messaging and online meetings remain largely functional.
- Microsoft To Do: The app may not load, and users may see operation failures.
- Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.
- SharePoint Online: Features that depend on Exchange Online may be impacted. Accessing files stored directly in SharePoint Online remains functional.
- Universal Print: Users may encounter errors submitting print jobs or using admin features.
- Windows 365: Customers who have configured their tenant and Cloud PCs to use Microsoft Purview Customer Key for Windows 365 Cloud PCs may have users who are unable to connect to their Cloud PCs.

Current status: We’re seeing positive results with our efforts to restart affected infrastructure. We’re actively monitoring the performance of these to verify stability which will support improved availability. Remediation actions will be expanded as we confirm stability with the changes applied.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Friday, November 13, 2026, at 2:30 AM UTC

11/12/2026 6:10:31 PM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Features of the Microsoft 365 services below that interact with Exchange Online and email services are impacted. Elements of those services that do not depend on interaction with Exchange Online remain functional.

- Exchange Online: Users may be unable to access their mailbox using Outlook on the web, Outlook desktop (MAPI), Exchange ActiveSync (EAS), or REST-based connections, and email delivery may be delayed.
- Microsoft 365 admin center: Admins may be unable to load some admin center pages.
- Microsoft 365 apps: Users may be unable to view their recently used files.
- Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory are affected.
- Microsoft 365 Education: Features including Assignments, Reading Progress, and Speaker Progress may be impacted.
- Microsoft Copilot 365: Users may be unable to load Copilot Chat or receive responses in the web and desktop apps, and Copilot experiences may be unable to access work data such as email, calendar, and files.
- Microsoft Defender for Office 365: Safe Links may be unable to verify URLs, which may impact users clicking links in Outlook and Teams.
- Microsoft Defender XDR: Users may be unable to load Microsoft Defender portal pages or solution tabs.
- Microsoft Fabric: Users may encounter failures when exporting reports with sensitivity labels to PDF or PowerPoint, when updating artifacts with sensitivity labels, or opening pbix with sensitivity label in Power BI Desktop. As a workaround, users can remove the sensitivity label from the affected item to complete the operation, if their organization's data protection policies allow it.
- Microsoft Graph: API requests that access Exchange Online data, such as mail, calendar, and contacts, may time out.
- Microsoft Intune
- Microsoft Planner: Users are experiencing Plan and Task operation reliability issues.
- Microsoft Purview: Multiple Purview services including Authorization, auto-labeling, Data Loss Prevention (DLP) across Microsoft 365 services, Communication Compliance, Information Protection label and auto-labeling policies, Role-Based Access Control (RBAC) and Data Classification are impacted, and users may be unable to open or load Microsoft Purview portal pages or protected content. Audit searches, protected content creation, eDiscovery tasks such as search and export, Data Classification and On Demand Scan features may also be impacted.
- Microsoft Teams: Scenarios that depend on Exchange Online, including calendar, meeting scheduling, and creating chats for organizations using Information Barriers, may fail. Core messaging and online meetings remain largely functional.
- Microsoft To Do: The app may not load, and users may see operation failures.
- Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.
- SharePoint Online: Features that depend on Exchange Online may be impacted. Accessing files stored directly in SharePoint Online remains functional.
- Universal Print: Users may encounter errors submitting print jobs or using admin features.
- Windows 365: Customers who have configured their tenant and Cloud PCs to use Microsoft Purview Customer Key for Windows 365 Cloud PCs may have users who are unable to connect to their Cloud PCs.

Current status: We’re applying infrastructure capacity improvements where possible in an effort to help support traffic in regions coming online. We’re continuing to monitor the results of changes applied so we can identify strategic actions that can help to improve service health across all affected regions.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Friday, November 13, 2026, at 3:00 AM UTC

11/12/2026 6:58:06 PM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Features of the Microsoft 365 services below that interact with Exchange Online and email services are impacted. Elements of those services that do not depend on interaction with Exchange Online remain functional.

- Exchange Online: Users may be unable to access their mailbox using Outlook on the web, Outlook desktop (MAPI), Exchange ActiveSync (EAS), or REST-based connections, and email delivery may be delayed.
- Microsoft 365 admin center: Admins may be unable to load some admin center pages.
- Microsoft 365 apps: Users may be unable to view their recently used files.
- Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory are affected.
- Microsoft 365 Education: Features including Assignments, Reading Progress, and Speaker Progress may be impacted.
- Microsoft Copilot 365: Users may be unable to load Copilot Chat or receive responses in the web and desktop apps, and Copilot experiences may be unable to access work data such as email, calendar, and files.
- Microsoft Defender for Office 365: Safe Links may be unable to verify URLs, which may impact users clicking links in Outlook and Teams.
- Microsoft Defender XDR: Users may be unable to load Microsoft Defender portal pages or solution tabs.
- Microsoft Fabric: Users may encounter failures when exporting reports with sensitivity labels to PDF or PowerPoint, when updating artifacts with sensitivity labels, or opening pbix with sensitivity label in Power BI Desktop. As a workaround, users can remove the sensitivity label from the affected item to complete the operation, if their organization's data protection policies allow it.
- Microsoft Graph: API requests that access Exchange Online data, such as mail, calendar, and contacts, may time out and prevent users from managing Teams, Channels, Membership, Apps management and send activity notifications using Graph API.
- Microsoft Intune: Scenarios including device enrollment, device check-in, and device compliance policies may have been intermittently impacted.
- Microsoft Planner: Users are experiencing Plan and Task operation reliability issues.
- Microsoft Purview: Multiple Purview services including Authorization, auto-labeling, Data Loss Prevention (DLP) across Microsoft 365 services, Communication Compliance, Information Protection label and auto-labeling policies, Role-Based Access Control (RBAC) and Data Classification are impacted, and users may be unable to open or load Microsoft Purview portal pages or protected content. Audit searches, protected content creation, eDiscovery tasks such as search and export, Data Classification and On Demand Scan features may also be impacted.
- Microsoft Teams: Most of the core functionality including joining calls, meetings, group chats, and channel messages are not impacted. Scenarios that depend on Exchange Online, including Calendar related failures with scheduling, invites, viewing, and meeting edits. Creation of Live or Virtual events fail. Failures with Copilot responses for outlook, calendar, or M365 files, read history, or adding to new chats. Navigating to App chats, adding new contacts or syncing contacts in settings fail. Standard channels are working fine but users may experience the inability to create or delete private or shared channels.
- Microsoft To Do: The app may not load, and users may see operation failures.
- Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.
- SharePoint Online: Features that depend on Exchange Online may be impacted. Accessing files stored directly in SharePoint Online remains functional.
- Universal Print: Users may encounter errors submitting print jobs or using admin features.
- Windows 365: Customers who have configured their tenant and Cloud PCs to use Microsoft Purview Customer Key for Windows 365 Cloud PCs may have users who are unable to connect to their Cloud PCs.

Current status: We’ve monitored the status of the changes applied to improve serviceability and confirmed that change is not taking as expected. We’re identifying alternate workstreams that can be applied to increase capacity in the face of sustained traffic management imbalances.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Friday, November 13, 2026, at 3:30 AM UTC

11/12/2026 7:36:01 PM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Features of the Microsoft 365 services below that interact with Exchange Online and email services are impacted. Elements of those services that do not depend on interaction with Exchange Online remain functional.

- Exchange Online: Users may be unable to access their mailbox using Outlook on the web, Outlook desktop (MAPI), Exchange ActiveSync (EAS), or REST based connections, and email delivery may be delayed.
- Microsoft 365 admin center: Admins may be unable to load some admin center pages.
- Microsoft 365 apps: Users may be unable to view their recently used files.
- Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory are affected.
- Microsoft 365 Education: Features including Assignments, Reading Progress, and Speaker Progress may be impacted.
- Microsoft Copilot 365: Users may be unable to load Copilot Chat or receive responses in the web and desktop apps, and Copilot experiences may be unable to access work data such as email, calendar, and files.
- Microsoft Defender for Office 365: Failures may occur for scenarios including access to Safe Links, Safe Attachments, protection and submission policies, and attempts to view Quarantine, Threat Explorer, and Email remediation events. Additionally, delays may occur for Tenant Allow / Block list changes, unified Role-Based Access Control, reporting, message traces, content extraction, and outbound protection. Users clicking on wrapped/rewritten URLs typically processed by Safe Links will result in a failure to navigate, as Safe Links fails to process it. Users who are able to successfully access the Quarantine portal may encounter failures when attempting to release items from quarantine.
- Microsoft Defender XDR: Users may be unable to load Microsoft Defender portal pages or solution tabs.
- Microsoft Fabric: Users may encounter failures when exporting reports with sensitivity labels to PDF or PowerPoint, when updating artifacts with sensitivity labels, or opening pbix with sensitivity label in Power BI Desktop. As a workaround, users can remove the sensitivity label from the affected item to complete the operation, if their organization's data protection policies allow it.
- Microsoft Graph: API requests that access Exchange Online data, such as mail, calendar, and contacts, may time out and prevent users from managing Teams, Channels, Membership, Apps management and send activity notifications using Graph API.
- Microsoft Intune: Scenarios including device enrollment, device check-in, and device compliance policies may have been intermittently impacted.
- Microsoft Planner: Users are experiencing Plan and Task operation reliability issues.
- Microsoft Purview: Multiple Purview services including Authorization, auto-labeling, Data Loss Prevention (DLP) across Microsoft 365 services, Communication Compliance, Information Protection label and auto-labeling policies, Role-Based Access Control (RBAC) and Data Classification are impacted, and users may be unable to open or load Microsoft Purview portal pages or protected content. Audit searches, protected content creation, eDiscovery tasks such as search and export, Data Classification and On Demand Scan features may also be impacted.
- Microsoft Teams: Most of the core functionality including joining calls, meetings, group chats, and channel messages are not impacted. Scenarios that depend on Exchange Online, including Calendar related failures with scheduling, invites, viewing, and meeting edits. Creation of Live or Virtual events fail. Failures with Copilot responses for outlook, calendar, or M365 files, read history, or adding to new chats. Navigating to App chats, adding new contacts or syncing contacts in settings fail. Standard channels are working fine but users may experience the inability to create or delete private or shared channels.
- Microsoft To Do: The app may not load, and users may see operation failures.
- Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.
- SharePoint Online: Features that depend on Exchange Online may be impacted. Accessing files stored directly in SharePoint Online remains functional.
- Universal Print: Users may encounter errors submitting print jobs or using admin features.
- Windows 365: Customers who have configured their tenant and Cloud PCs to use Microsoft Purview Customer Key for Windows 365 Cloud PCs may have users who are unable to connect to their Cloud PCs.

Current status: As part of our investigation into the sustained traffic management imbalances, we’re reviewing traffic flows and affected infrastructure to identify opportunities to optimize routing. This includes verifying the reasons for service failures so we can develop specific actions to improve stability.

We will continue to share more information as soon as we have it, and for now we can confirm that there is no indication this is the result of malicious activity. We’ll continue to apply learnings towards remediation actions as we confirm effectiveness mitigation actions.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Friday, November 13, 2026, at 4:30 AM UTC

11/12/2026 8:12:23 PM 

Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Features of the Microsoft 365 services below that interact with Exchange Online and email services are impacted. Elements of those services that do not depend on interaction with Exchange Online remain functional.

- Exchange Online: Users may be unable to access their mailbox using Outlook on the web, Outlook desktop (MAPI), Exchange ActiveSync (EAS), or REST-based connections, and email delivery may be delayed.
- Microsoft 365 admin center: Admins may be unable to load some admin center pages.
- Microsoft 365 apps: Users may be unable to view their recently used files.
- Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory are affected.
- Microsoft 365 Education: Features including Assignments, Reading Progress, and Speaker Progress may be impacted.
- Microsoft Copilot 365: Users may be unable to load Copilot Chat or receive responses in the web and desktop apps, and Copilot experiences may be unable to access work data such as email, calendar, and files.
- Microsoft Defender for Office 365: Failures may occur for scenarios including access to Safe Links, Safe Attachments, protection and submission policies, and attempts to view Quarantine, Threat Explorer, and Email remediation events. Additionally, delays may occur for Tenant Allow / Block list changes, unified Role-Based Access Control, reporting, message traces, content extraction, and outbound protection. Users clicking on wrapped/rewritten URLs typically processed by Safe Links will result in a failure to navigate, as Safe Links fails to process it. Users who are able to successfully access the Quarantine portal may encounter failures when attempting to release items from quarantine.
- Microsoft Defender XDR: Users may be unable to load Microsoft Defender portal pages or solution tabs.
- Microsoft Fabric: Users may encounter failures when exporting reports with sensitivity labels to PDF or PowerPoint, when updating artifacts with sensitivity labels, or opening pbix with sensitivity label in Power BI Desktop. As a workaround, users can remove the sensitivity label from the affected item to complete the operation, if their organization's data protection policies allow it.
- Microsoft Graph: API requests that access Exchange Online data, such as mail, calendar, and contacts, may time out and prevent users from managing Teams, Channels, Membership, Apps management and send activity notifications using Graph API.
- Microsoft Intune: Scenarios including device enrollment, device check-in, and device compliance policies may have been intermittently impacted.
- Microsoft Planner: Users are experiencing Plan and Task operation reliability issues.
- Microsoft Purview: Multiple Purview services including Authorization, auto-labeling, Data Loss Prevention (DLP) across Microsoft 365 services, Communication Compliance, Information Protection label and auto-labeling policies, Role-Based Access Control (RBAC) and Data Classification are impacted, and users may be unable to open or load Microsoft Purview portal pages or protected content. Audit searches, protected content creation, eDiscovery tasks such as search and export, Data Classification and On Demand Scan features may also be impacted.
- Microsoft Teams: Most of the core functionality including joining calls, meetings, group chats, and channel messages are not impacted. Scenarios that depend on Exchange Online, including Calendar related failures with scheduling, invites, viewing, and meeting edits. Creation of Live or Virtual events fail. Failures with Copilot responses for outlook, calendar, or M365 files, read history, or adding to new chats. Navigating to App chats, adding new contacts or syncing contacts in settings fail. Standard channels are working fine but users may experience the inability to create or delete private or shared channels.
- Microsoft To Do: The app may not load, and users may see operation failures.
- Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.
- SharePoint Online: Features that depend on Exchange Online may be impacted. Accessing files stored directly in SharePoint Online remains functional.
- Universal Print: Users may encounter errors submitting print jobs or using admin features.
- Windows 365: Customers who have configured their tenant and Cloud PCs to use Microsoft Purview Customer Key for Windows 365 Cloud PCs may have users who are unable to connect to their Cloud PCs.

Current status: We’re continuing our efforts to improve server stability to improve traffic flow. This includes adjusting traffic protocols, redistributing traffic, and applying strategic traffic blocking measures.

We're observing partial recovery across regions in which we've applied these adjustments; however, these actions aren't resulting in sustained recovery, so we're reviewing what additional actions we can take to improve overall infrastructure stability.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Friday, November 13, 2026, at 5:00 AM UTC

11/12/2026 8:56:39 PM
Title: Users may be unable to connect to multiple Microsoft 365 services

User impact: Users may be unable to connect to multiple Microsoft 365 services.

More info: Features of the Microsoft 365 services below that interact with Exchange Online and email services are impacted. Elements of those services that do not depend on interaction with Exchange Online remain functional.

- Exchange Online: Users may be unable to access their mailbox using Outlook on the web, Outlook desktop (MAPI), Exchange ActiveSync (EAS), or REST-based connections, and email delivery may be delayed.
- Microsoft 365 admin center: Admins may be unable to load some admin center pages.
- Microsoft 365 apps: Users may be unable to view their recently used files.
- Microsoft 365 Apps Admin Center: Multiple services including Cloud Update, Cloud Policy, and Inventory are affected.
- Microsoft 365 Education: Features including Assignments, Reading Progress, and Speaker Progress may be impacted.
- Microsoft Copilot 365: Users may be unable to load Copilot Chat or receive responses in the web and desktop apps, and Copilot experiences may be unable to access work data such as email, calendar, and files.
- Microsoft Defender for Office 365: Failures may occur for scenarios including access to Safe Links, Safe Attachments, protection and submission policies, and attempts to view Quarantine, Threat Explorer, and Email remediation events. Additionally, delays may occur for Tenant Allow / Block list changes, unified Role-Based Access Control, reporting, message traces, content extraction, and outbound protection. Users clicking on wrapped/rewritten URLs typically processed by Safe Links will result in a failure to navigate, as Safe Links fails to process it. Users who are able to successfully access the Quarantine portal may encounter failures when attempting to release items from quarantine.
- Microsoft Defender XDR: Users may be unable to load Microsoft Defender portal pages or solution tabs.
- Microsoft Fabric: Users may encounter failures when exporting reports with sensitivity labels to PDF or PowerPoint, when updating artifacts with sensitivity labels, or opening pbix with sensitivity label in Power BI Desktop. As a workaround, users can remove the sensitivity label from the affected item to complete the operation, if their organization's data protection policies allow it.
- Microsoft Graph: API requests that access Exchange Online data, such as mail, calendar, and contacts, may time out and prevent users from managing Teams, Channels, Membership, Apps management and send activity notifications using Graph API.
- Microsoft Intune: Scenarios including device enrollment, device check-in, and device compliance policies may have been intermittently impacted.
- Microsoft Planner: Users are experiencing Plan and Task operation reliability issues.
- Microsoft Purview: Multiple Purview services including Authorization, auto-labeling, Data Loss Prevention (DLP) across Microsoft 365 services, Communication Compliance, Information Protection label and auto-labeling policies, Role-Based Access Control (RBAC) and Data Classification are impacted, and users may be unable to open or load Microsoft Purview portal pages or protected content. Audit searches, protected content creation, eDiscovery tasks such as search and export, Data Classification and On Demand Scan features may also be impacted.
- Microsoft Teams: Most of the core functionality including joining calls, meetings, group chats, and channel messages are not impacted. Scenarios that depend on Exchange Online, including Calendar related failures with scheduling, invites, viewing, and meeting edits. Creation of Live or Virtual events fail. Failures with Copilot responses for outlook, calendar, or M365 files, read history, or adding to new chats. Navigating to App chats, adding new contacts or syncing contacts in settings fail. Standard channels are working fine but users may experience the inability to create or delete private or shared channels.
- Microsoft To Do: The app may not load, and users may see operation failures.
- Power BI: All users may intermittently be unable to export reports with MIP sensitivity labels to PDF in Power BI.
- SharePoint Online: Features that depend on Exchange Online may be impacted. Accessing files stored directly in SharePoint Online remains functional.
- Universal Print: Users may encounter errors submitting print jobs or using admin features.
- Windows 365: Customers who have configured their tenant and Cloud PCs to use Microsoft Purview Customer Key for Windows 365 Cloud PCs may have users who are unable to connect to their Cloud PCs.

Current status: We appreciate your organization’s patience and understanding while we work with urgency to resolve this incident.

As we’ve applied our current ongoing mitigation actions, we’ve observed a surge in outbound call volume from our routing services to our backend servers. This occurs when the backend servers outbound service cannot properly route to the backend machines. We’re continuing to observe heightened volume due to traffic rebalancing actions that we have taken throughout this event. We’re working on multiple workstreams to pinpoint the underlying cause of this traffic influx and address it.

Current actions we are taking include scaling up virtual machines to increase capacity and reduce load. Additionally, we’re querying for machines in a bad state to perform a force sync for our recent network change, which may improve service availability. However, we are encountering issues with the machines being stuck in a bad state, preventing our changes from syncing as expected. We’ll continue to monitor the effectiveness of changes applied so we can determine what refinements are necessary.

Scope of impact: This issue may affect users attempting to access the affected Microsoft 365 services.

Next update by: Friday, November 13, 2026, at 6:00 AM UTC

Microsoft Service Health Updates for EX1550543

EX1550543 - Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

Impacting: Exchange Online; Estimated start time: Thursday, November 12, 2026 8:17 AM

Skip to Latest Update Included

11/12/2026 8:20:07 AM 

Title: Potential issues accessing mailboxes via one or more connection methods

User impact: Users may experience errors or failures when accessing their mailbox via one or more Exchange Online connection methods.

Current status: We're investigating a potential issue and checking for impact to your organization. We'll provide an update within 60 minutes.

11/12/2026 8:55:02 AM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Current status: We’re reviewing service health telemetry information to identify and isolate any errors contributing to impact for further investigation.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Thursday, November 12, 2026, at 6:00 PM UTC

11/12/2026 9:45:30 AM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Current status: We’ve identified connectivity errors occurring on a portion of Exchange Online infrastructure which receives and processes users’ access requests. We’ve collected networking logs to review to further investigate the source of these errors and confirm our next steps.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Thursday, November 12, 2026, at 8:00 PM UTC

11/12/2026 10:19:37 AM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Current status: Our investigation indicates that the affected infrastructure is experiencing elevated load across multiple regions, which is contributing to the connectivity errors users are receiving. We're restarting and repairing impacted portions of this infrastructure to mitigate impact and are evaluating options to redirect traffic to alternate infrastructure to expedite relief.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Thursday, November 12, 2026, at 7:30 PM UTC

11/12/2026 10:29:00 AM 

We've redirected a portion of traffic away from the affected infrastructure in the US to reduce load, and we're evaluating doing the same in other regions. While Exchange is the primarily impacted service, we've identified additional Microsoft 365 services that are also experiencing connectivity issues, and we're communicating those issues under MO1550821 on the Service Health Dashboard.

This quick update is designed to give the latest information on this issue.

11/12/2026 10:43:38 AM 

We've identified a pattern in which affected servers are becoming intermittently unavailable, which places additional strain on the remaining infrastructure and contributes to the connectivity issues users are experiencing. We've begun redistributing Outlook connection traffic across our broader worldwide infrastructure to help balance the load, which may result in some latency while this change is in effect, and we're reviewing recent changes to identify the source of the increased traffic.

This quick update is designed to give the latest information on this issue.

11/12/2026 10:57:48 AM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Current status: We've completed redistributing Outlook connection traffic across our worldwide infrastructure, and we're moving additional traffic off the affected infrastructure to further reduce load. We're also restarting affected servers to return them to service. In parallel, we're investigating whether the elevated traffic reflects a genuine increase in requests or a shift in how traffic is being routed across our infrastructure.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Thursday, November 12, 2026, at 8:00 PM UTC

11/12/2026 11:06:57 AM 

We're aggressively pursuing all pathways to reduce impact. As a precaution, we've paused all deployments and configuration changes while we review recent changes for any correlation to this event. We've also moved traffic for some services off the affected infrastructure to further reduce load, with additional traffic moves in progress.

This quick update is designed to give the latest information on this issue.

11/12/2026 11:18:39 AM 

We've determined that the elevated load isn't driven by an overall increase in traffic, but by a large number of servers being unexpectedly unavailable, which is shifting load onto the remaining infrastructure. We're investigating what's causing these servers to become unavailable while we work to safely return them to service.

This quick update is designed to give the latest information on this issue.

11/12/2026 11:43:16 AM 

We've identified that affected servers are failing automated health checks, which is causing them to become unavailable, and this may be related to a recent change to a component involved in processing those checks. We're testing a configuration change on a subset of affected infrastructure to address this and, if successful, will apply it more broadly. In parallel, we've initiated a restart of all affected servers and are validating whether they're successfully returning to service.

This quick update is designed to give the latest information on this issue.

Next update by: Thursday, November 12, 2026, at 8:00 PM UTC

11/12/2026 11:57:18 AM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: While we haven't identified any recent changes that correlate with the start of impact, our investigation indicates the failed health checks may originate from a specific component on the affected servers that's responsible for processing them. We're deploying a targeted change to bypass this component on a subset of servers to validate whether this restores availability, and we've taken steps to prevent additional servers from being removed from service while we work to return the affected servers to service. We're also investigating why affected servers are experiencing elevated processor usage while handling requests.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Thursday, November 12, 2026, at 9:00 PM UTC

11/12/2026 12:38:14 PM 

While validating the targeted change, we found that many of the affected servers have become unresponsive, which is preventing us from confirming whether the change is effective. We're restarting these servers so they can come back online with the change in place, and we're applying the same approach to additional affected portions of our infrastructure to validate the results more broadly.

Next update by: Thursday, November 12, 2026, at 9:00 PM UTC

This quick update is designed to give the latest information on this issue.

11/12/2026 12:56:16 PM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: We've validated an alternative health check method on a subset of affected infrastructure, which allowed the servers in that subset to successfully return to service, and we're now applying this change more broadly. We're also preparing an automated recovery process to continually detect and restart unresponsive servers, to help keep them in service while this change progresses. Additionally, our review of recent changes has identified a small number of configuration updates that we're investigating as potential contributors to the issue.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Thursday, November 12, 2026, at 10:00 PM UTC

11/12/2026 1:31:44 PM 

We're continuing to work through restarting and validating the affected servers to safely return them to service, and we're exploring opportunities to expedite this process. In parallel, we're assessing whether reverting the small number of recent configuration updates we identified could help accelerate recovery.

Next update by: Thursday, November 12, 2026, at 10:00 PM UTC

This quick update is designed to give the latest information on this issue.

11/12/2026 2:00:29 PM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: We’re continuing to pursue all available pathways to restore service, as our actions taken thus far have not provided the anticipated relief. Our investigation has found that a core process on the affected servers is becoming overwhelmed, which causes the servers to stop responding and contributes to the capacity loss.

To validate a potential recovery approach, we're fully isolating a portion of our service infrastructure, restarting the affected components, and gradually reintroducing traffic to confirm our services remain stable before applying this approach more broadly. We're also analyzing traffic patterns across our entire service infrastructure and evaluating whether isolating traffic within each region may allow affected regions to recover independently.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Thursday, November 12, 2026, at 11:00 PM UTC

11/12/2026 2:57:29 PM

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: We've begun returning a portion of the affected servers to service, and they're remaining stable so far. We’ve also shifted traffic and connections to alternative pathways wherever possible and have observed limited recovery in some regions.

We've streamlined our recovery process to expedite returning the remaining affected servers to service. To further support recovery, we're implementing protective traffic management measures in a specific location to reduce load on the affected infrastructure, and we'll expand these measures to additional locations if we observe positive results. As capacity is restored, users may experience a gradual recovery as their clients reconnect to the service.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Friday, November 13, 2026, at 12:00 AM UTC

11/12/2026 3:59:42 PM

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: While the servers we've returned to service initially remain healthy, we've observed that they can become unresponsive again once they begin receiving traffic. We're analyzing diagnostic data from these servers with our networking and platform experts to determine what's triggering this behavior.

Building on the protective traffic management measures we've implemented, we're also temporarily limiting which types of traffic can reach the affected infrastructure in specific locations. This will help us determine whether a particular type of request is contributing to the impact and allow us to restore service incrementally. Additionally, we're rebuilding a subset of affected servers using a previous software configuration to validate whether this prevents them from becoming unresponsive, and we'll expand this approach to additional servers if we observe positive results.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Friday, November 13, 2026, at 1:00 AM UTC

11/12/2026 5:06:41 PM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: Our investigation has found that a process on the affected servers responsible for establishing secure connections becomes overwhelmed, causing the servers to stop processing requests. We're preparing a configuration change to address this behavior that can be applied across all affected servers, and we're validating it on a subset of servers before applying it more broadly alongside restarts of the affected infrastructure. In parallel, we've begun reverting a recent network configuration change that correlates with the start of impact and are monitoring to determine whether this contributes to recovery.

The temporary traffic limitations we previously described are now in effect in specific locations. We're monitoring the affected servers in those locations to confirm whether they remain stable while handling a narrower set of connections, after which we'll gradually reintroduce additional traffic.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Friday, November 13, 2026, at 2:00 AM UTC

11/12/2026 5:45:44 PM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: We’re seeing positive results with our efforts to restart affected infrastructure. We’re actively monitoring the performance of these to verify stability which will support improved availability. Remediation actions will be expanded as we confirm stability with the changes applied.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Friday, November 13, 2026, at 3:00 AM UTC

11/12/2026 6:09:06 PM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: We’re applying infrastructure capacity improvements where possible in an effort to help support traffic in regions coming online. We’re continuing to monitor the results of changes applied so we can identify strategic actions that can help to improve service health across all affected regions.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Friday, November 13, 2026, at 3:30 AM UTC

11/12/2026 6:54:05 PM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: We’ve monitored the status of the changes applied to improve serviceability and confirmed that change is not taking as expected. We’re identifying alternate workstreams that can be applied to increase capacity in the face of sustained traffic management imbalances.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Friday, November 13, 2026, at 4:00 AM UTC

11/12/2026 7:34:14 PM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: As part of our investigation into the sustained traffic management imbalances, we’re reviewing traffic flows and affected infrastructure to identify opportunities to optimize routing. This includes verifying the reasons for service failures so we can develop specific actions to improve stability.

We will continue to share more information as soon as we have it, and for now we can confirm that there is no indication this is the result of malicious activity. We’ll continue to apply learnings towards remediation actions as we confirm effectiveness mitigation actions.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Friday, November 13, 2026, at 4:30 AM UTC

11/12/2026 8:10:49 PM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: We’re continuing our efforts to improve server stability to improve traffic flow. This includes adjusting traffic protocols, redistributing traffic, and applying strategic traffic blocking measures.

We're observing partial recovery across regions in which we've applied these adjustments; however, these actions aren't resulting in sustained recovery, so we're reviewing what additional actions we can take to improve overall infrastructure stability.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Friday, November 13, 2026, at 5:30 AM UTC

11/12/2026 8:59:46 PM 

Title: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods

User impact: Users may be unable to connect to their mailboxes in Exchange Online through multiple connection methods.

More info: Potentially impacted connection methods may include:
- Outlook on the web
- Messaging API (MAPI)
- Exchange ActiveSync (EAS)
- Representational State Transfer (REST) API

Impact to additional Microsoft 365 services is described under MO1550821 in the Service Health Dashboard.

Current status: We appreciate your organization’s patience and understanding while we work with urgency to resolve this incident.

As we’ve applied our current ongoing mitigation actions, we’ve observed a surge in outbound call volume from our routing services to our backend servers. This occurs when the backend servers outbound service cannot properly route to the backend machines.

We’re continuing to observe heightened volume due to traffic rebalancing actions that we have taken throughout this event. We’re working on multiple workstreams to pinpoint the underlying cause of this traffic influx and address it.

Actions we're currently taking include scaling up virtual machines to increase capacity and reduce load. Additionally, we’re querying for machines in a bad state to perform a force sync for our recent network change, which may improve service availability. However, we are encountering issues with the machines being stuck in a bad state, preventing our changes from syncing as expected. We’ll continue to monitor the effectiveness of changes applied so we can determine what refinements are necessary.

Scope of impact: This issue may affect users attempting to access their mailbox in Exchange Online using the affected connection methods.

Next update by: Friday, November 13, 2026, at 6:30 AM UTC

Here's how ENow's Monitoring for Microsoft 365 is tracking this outage in real time  

When the outage occurred, ENow customers didn’t have to guess whether the issue was local, user-specific, or systemic.  

Overall Impact

Network Status

Exchange Online Impact

Microsoft Teams Impact flagging Calendar and Exchange Integration

We'll continue to update this post as the outage updates evolve!

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Learn about ENow's Microsoft 365 Monitoring and Reporting Platform, or contact us for a Microsoft 365 Monitoring Demo.