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Microsoft 365 outage takes down Outlook, Teams and the status page

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Microsoft 365 went down on Thursday, November 12, 2026, leaving many users unable to reach Outlook mail (Exchange Online), Microsoft Teams, SharePoint Online, Microsoft 365 Copilot, Defender XDR, Planner and To Do, while Microsoft’s own status page struggled to load. Microsoft first acknowledged the problem at 17:54 UTC; in its update at 20:32 UTC it said affected servers are failing automated health checks, possibly because of one component that processes those checks, and that it is testing a change to bypass it. The issue was still listed as a service degradation at 20:43 UTC, with the next update promised by 9:30 PM UTC, according to the Microsoft 365 status feed.

What’s new

The first sign came from the Microsoft 365 Status account on X at 17:54 UTC. Microsoft said it was investigating reports of users having trouble reaching Exchange Online mailboxes “through multiple connection methods in the Americas”, and pointed admins to incident EX1550543 in the Microsoft 365 admin center.

The problem soon spread beyond mail. About twenty minutes later, a Hacker News thread titled “Ask HN: Microsoft/Azure Outage?” reached the front page, with the poster saying all of their company’s Microsoft cloud connections had been down for five minutes and that the status page would not load. Many commenters reported the same, and several noted that Microsoft’s own status page was slow or failing to load during the outage. A second thread, “Outlook is down, and so is Microsoft’s status page”, passed 200 points within a few hours.

User reports on Downdetector climbed fast. GV Wire, which tracked the Outlook page through the morning, counted more than 2,400 reports at 9:50 a.m. Pacific (17:50 UTC), more than 65,000 at 10:08 a.m. and more than 600,000 at 11:25 a.m. (19:25 UTC). Downdetector counts user complaints, not confirmed failures, so treat the numbers as a sign of scale rather than an exact count.

Microsoft’s status update at 20:32 UTC lists these services as potentially affected:

Service What it covers
Exchange Online Outlook mail and calendars for work and school accounts
Microsoft Teams Chat, calls and meetings
SharePoint Online Team sites and the files behind them
Microsoft Copilot 365 Copilot inside Microsoft 365 apps
Microsoft Defender XDR Microsoft’s security monitoring and response portal
Microsoft Planner Team task boards
Microsoft To Do Personal task lists

What Microsoft has said about the cause so far, in the order it said it:

  • In an earlier update quoted in the Hacker News thread, Microsoft said the affected infrastructure was “experiencing elevated load across multiple regions”, that it was restarting and repairing parts of it, and that it was looking at an unexpected rise in one type of service traffic and at moving traffic to other infrastructure.
  • At 19:30 UTC it said the load is not caused by more traffic overall, but by many servers dropping out and shifting their work onto the remaining ones. It is investigating why those servers became unavailable.
  • As a precaution, Microsoft has paused “all deployments and configuration changes” while it checks whether a recent change is linked to the outage.
  • At 19:52 UTC, according to the status feed as quoted on Hacker News, Microsoft said the affected servers were “failing automated health checks, which is causing them to become unavailable”, possibly because of a recent change to a component that processes those checks. Hacker News commenters said Microsoft later took that update down and showed the 19:30 UTC one again.
  • At 20:32 UTC it said it had not found any recent change that lines up with the start of the outage. It suspects a specific component on the affected servers that processes the health checks, is deploying a change to bypass that component on a subset of servers to see if they come back, and has stopped more servers from being removed from service. It is also looking into why the affected servers are using more processor time than normal.

Microsoft has not said the outage was caused by an attack, and it has not given a time for a full fix.

Is Azure down?

The Hacker News thread asked about Azure, but the Azure status page showed “no active events” when we checked at 19:46 UTC, and its RSS feed still listed no incidents at 20:36 UTC. Azure’s public page is only used for widespread incidents, so a problem limited to some subscriptions would show up in Azure Service Health inside the Azure portal instead. On the evidence so far, this is a Microsoft 365 outage rather than an Azure one.

What it means for developers

If your team or your app depends on Microsoft 365, a few things are worth doing now:

  • Watch the right feeds. The public page at status.cloud.microsoft only carries the biggest incidents, and it is a JavaScript app that failed to load for many people today. Its RSS feed (https://status.cloud.microsoft/api/feed/mac) kept posting updates throughout. Admins get the full timeline under EX1550543 in the Microsoft 365 admin center (Health > Service health), and the Microsoft 365 Status account on X posts major updates.
  • Expect failures in Microsoft Graph calls. Apps that read mail, calendars, Teams messages or SharePoint files through Microsoft Graph may see errors or timeouts while the services are degraded. Retry with backoff instead of hammering the API, and queue writes such as sent mail or posted messages until the services recover.
  • Don’t trust a quiet status page. As several Hacker News commenters pointed out, the status page itself struggled during the outage. Your own monitoring and synthetic checks will usually tell you sooner.
  • Hold off on risky changes. Microsoft froze its own deployments; it is a sensible moment to avoid tenant-wide changes to mail flow, Conditional Access or Teams policies until the incident is closed, so you are not chasing two problems at once.

If you run a site of your own, a clear maintenance page that returns a 503 status helps users and search engines during downtime; we have a free site maintenance page template with nginx, Apache and Cloudflare setups.

We will update this post when Microsoft shares a cause or confirms the services have recovered.

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