What is happening?
Microsoft is working through a service disruption affecting Exchange Online and other Microsoft 365 services. Users may have trouble opening Outlook/email or connecting to affected applications. The disruption is not limited to one business, but impact can differ by service, region, and organization.
The latest recovery update
Microsoft reports that some restored Exchange Online servers can become unresponsive again when traffic reaches them. Recovery work is continuing. Outlook/email and other Microsoft 365 services may still be unavailable or intermittent. Microsoft has not announced full restoration or a confirmed restoration time.
Why recovery has taken time
Microsoft reports that affected servers became unavailable, placing more load on the remaining infrastructure. It tested health-check changes and restarted servers, but later said those actions had not provided the wider relief expected. Recovery work then included isolating parts of the infrastructure, restarting components, and gradually restoring traffic to test stability.
Which services may be affected?
Microsoft identifies potential impact to Exchange Online, Teams, SharePoint Online, Copilot, Defender, Planner, To Do, Intune, several Purview services, Microsoft 365 Apps Admin Center, and Universal Print. It also reports a specific Power BI issue exporting sensitivity-labeled reports to PDF. This does not mean every feature or every user of these services is down.
What this means for your business
Service may return at different times for different applications and organizations. A successful sign-in or one working app does not establish that every affected service has recovered. Microsoft's general recovery updates also do not confirm the status of any individual client environment.
Today's update timeline
The accompanying timeline summarizes every timestamped update available in the public Microsoft incident extract for EX1550543 and MO1550821 through 5:59:42 PM CST on November 12. All times are Central Standard Time. It distinguishes Microsoft's update times from the time this status was checked.
Today's incident updates
All 27 available timestamped EX1550543 and MO1550821 updates on November 12, 2026. Times are Microsoft-issued update times converted to CST, newest first.
5:59:42 PM CST | EX1550543
Microsoft reports that restored servers can become unresponsive again under traffic. It is testing traffic restrictions and rebuilding a subset of servers with a previous software configuration to support recovery.
4:58:28 PM CST | MO1550821
Limited recovery is observed in some regions. Some returned servers are stable so far. Recovery may be gradual as apps reconnect; protective traffic management is being tested.
4:57:29 PM CST | EX1550543
Limited recovery is observed in some regions. Some returned servers are stable so far. Microsoft is returning more servers and shifting traffic to alternate paths.
4:03:00 PM CST | MO1550821
Earlier actions have not provided the expected relief. Microsoft is isolating infrastructure, restarting components, and gradually reintroducing traffic to test stability.
4:00:29 PM CST | EX1550543
Earlier actions have not provided the expected relief. An overwhelmed core process is making servers unresponsive. Isolation, restarts, and gradual traffic reintroduction are being tested.
3:31:54 PM CST | MO1550821
Microsoft continues restarting and validating servers and is assessing whether reversing a small number of configuration updates could speed recovery.
3:31:44 PM CST | EX1550543
Microsoft continues restarting and validating servers and is assessing whether reversing a small number of configuration updates could speed recovery.
2:57:05 PM CST | MO1550821
An alternative health-check method returned a subset of servers to service. Microsoft is expanding the change and preparing automated recovery for unresponsive servers.
2:56:16 PM CST | EX1550543
An alternative health-check method returned a subset of servers to service. Microsoft is expanding the change and preparing automated recovery for unresponsive servers.
2:38:42 PM CST | MO1550821
Many affected servers became unresponsive during testing. Microsoft is restarting them with the targeted change in place and expanding validation.
2:38:14 PM CST | EX1550543
Many affected servers became unresponsive during testing. Microsoft is restarting them with the targeted change in place and expanding validation.
1:58:41 PM CST | MO1550821
Microsoft is testing a change to bypass a component involved in failed health checks. It is preventing more servers from being removed from service and investigating high processor usage.
1:57:18 PM CST | EX1550543
Microsoft is testing a change to bypass a component involved in failed health checks. It is preventing more servers from being removed from service and investigating high processor usage.
1:43:19 PM CST | MO1550821
Failed automated health checks are making servers unavailable. Microsoft is testing a configuration change on a subset of infrastructure and restarting affected servers.
1:43:16 PM CST | EX1550543
Failed automated health checks are making servers unavailable. Microsoft is testing a configuration change on a subset of infrastructure and restarting affected servers.
1:30:15 PM CST | MO1550821
Microsoft has paused deployments and configuration changes. It says unavailable servers, rather than an overall traffic increase, are shifting load to remaining infrastructure.
1:18:39 PM CST | EX1550543
Microsoft says the elevated load comes from unexpectedly unavailable servers, not an overall increase in traffic. It is investigating why those servers are unavailable.
1:06:57 PM CST | EX1550543
Microsoft has paused deployments and configuration changes as a precaution and is moving additional service traffic off affected infrastructure.
12:58:10 PM CST | MO1550821
Connection traffic has been redistributed across worldwide infrastructure. Additional traffic moves and server restarts continue while Microsoft investigates the elevated load.
12:57:48 PM CST | EX1550543
Outlook connection traffic has been redistributed across worldwide infrastructure. Additional traffic moves and server restarts continue while Microsoft investigates the elevated load.
12:43:38 PM CST | EX1550543
Intermittently unavailable servers are placing extra strain on remaining infrastructure. Microsoft begins redistributing Outlook traffic worldwide and warns this may add latency.
12:29:00 PM CST | EX1550543
Some US traffic has been redirected to reduce load. Microsoft identifies additional affected Microsoft 365 services under MO1550821.
12:27:35 PM CST | MO1550821
Microsoft opens a broader Microsoft 365 connectivity incident, citing elevated infrastructure load across regions and potential impact to Exchange, Teams, SharePoint, Copilot, and Defender XDR.
12:19:37 PM CST | EX1550543
Elevated infrastructure load across multiple regions is contributing to connection errors. Microsoft is restarting and repairing affected infrastructure and considering alternate traffic routes.
11:45:30 AM CST | EX1550543
Microsoft identifies connection errors in Exchange infrastructure that handles access requests and collects network logs to investigate.
10:55:02 AM CST | EX1550543
Microsoft reviews service-health information to identify errors contributing to mailbox access problems.
10:20:07 AM CST | EX1550543
Microsoft begins investigating potential errors or failures accessing Exchange Online mailboxes through one or more connection methods.
Source: Microsoft incident notices reproduced by Penn IT.
https://mailservices.isc.upenn.edu/computing/email/penno365/alerts/ms-incidents.html
