TL;DR
- Microsoft is working to restore Exchange Online after a Microsoft 365 outage left many users unable to reach their mailboxes on November 12.
- Microsoft first reported the problem at 11:54 a.m. CT under incident EX1550543, and it may affect users in any region.
- Microsoft has not named a root cause yet, though it says elevated load on part of its infrastructure is likely contributing.
- As of 1:12 p.m. CT, Microsoft was rerouting traffic and restarting affected servers, with the next update due by 3:00 p.m. CT.
Microsoft is working to restore Exchange Online after a Microsoft 365 outage left many users unable to reach their mailboxes on Thursday, November 12. Microsoft first reported the problem at 11:54 a.m. CT under incident EX1550543. The issue began in the Americas, and Microsoft later confirmed it may affect users in any region.
The outage reaches past Outlook. Microsoft lists Exchange Online, Microsoft Teams, SharePoint Online, Microsoft 365 Copilot, and Microsoft Defender XDR as potentially affected services. Outlook on the web, the desktop Outlook connection, mobile mail through Exchange ActiveSync, and the REST API are all listed as affected ways to connect. Outlook problem reports on Downdetector peaked at about 130,000, according to Tom's Guide, and TechRadar counted more than 120,000 at once. Those are only the people who stopped to file a report, so the real number of affected users is far higher. Our own help desk has taken a steady stream of Outlook outage calls today.
Microsoft has not named a root cause yet. At 12:35 p.m. CT, the company said a portion of its infrastructure was under elevated load across multiple regions, and that this load is likely contributing to the connection errors. Microsoft says it is still investigating whether that traffic reflects a real increase in requests or a change in how traffic is being routed. Nothing Microsoft has published links this outage to this week's Outlook security update, so that patch should still be installed.
Recovery work is underway. Microsoft has redistributed connection traffic across its worldwide infrastructure, and it is moving more traffic off the strained systems. The company also says it has paused all deployments and is restarting affected servers to return them to service. As of 1:12 p.m. CT, the outage was still ongoing, and Microsoft's next update is due by 3:00 p.m. CT.
While Microsoft finishes the fix, check the Microsoft 365 Service Health page in the admin center, or the public status page at status.cloud.microsoft if the admin center will not load. The @MSFT365Status account on X is posting updates as well. Switching from desktop Outlook to the web or the phone app may not help this time, because Microsoft lists those connection methods as affected too.
Please avoid rebuilding Outlook profiles, reinstalling Office, or resetting passwords to fix this problem. The fault is on Microsoft's side, and those changes can create additional work once service returns. Use the phone or another channel for anything urgent, and tell customers that email replies may be delayed today. Be careful with any message that claims to be an outage notice and asks you to sign in, because scammers often copy real events.
Cloud email is very reliable most days, and a short plan makes the rare bad day much easier to handle. Athens businesses can call My I.T. Consultants, a Microsoft-certified MSP, at 903-675-5431 for help checking Microsoft 365 service health and planning for the next outage. Our office hours are Monday through Friday from 7:00 a.m. to 6:00 p.m.
Want help with this at your business? See Cloud Services on our Services page or contact My I.T. Consultants.
