Bad newsMicrosoft Outage Cuts Outlook, Teams and Copilot for Users Worldwide, 130,000 Report Problems
Microsoft says unexpectedly unavailable servers strained the rest of its infrastructure on Thursday, disrupting Outlook, Teams and Copilot in the US and beyond. Downdetector logged about 130,000 Outlook reports, and the company gave no restoration time.
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A widespread Microsoft outage disrupted Outlook, Teams and the Copilot AI assistant on Thursday 12 November, leaving workers unable to send email, open inboxes or join messaging apps. The company says the cause was servers that unexpectedly became unavailable and strained those still running. It did not say when service would be fully restored.
The BBC reports that problems started in the United States but could affect users “in any region”. The monitoring site Downdetector showed more than 131,000 reports of Outlook problems in the US at 18:15 GMT, and a spike in UK reports at about 18:30 GMT. Al Jazeera puts the Outlook count at about 130,000 shortly after 1pm Eastern Time, falling to about 77,000 by just before 3pm Eastern (20:00 GMT).
Microsoft’s first explanation was that part of its infrastructure was under “elevated load”. A later update changed the account. The company said the load was not caused by more traffic. It said a number of servers were “unexpectedly unavailable”, which strained the remaining infrastructure.
At 19:50 GMT it said it was testing a configuration change to fix the problem. The fault, it said, was “causing servers to fail automated health checks and become unavailable”. All affected servers had been restarted, it added. Al Jazeera quotes a Microsoft post on X saying it was working “to safely return them to service”. The outlet says the change was meant to redistribute traffic that had risen on parts of the infrastructure.
| Time (GMT) | What was reported | Source |
|---|---|---|
| About 18:00 | Outlook reports reach about 130,000 | Al Jazeera, citing Downdetector |
| 18:15 | More than 131,000 US Outlook reports | BBC, citing Downdetector |
| About 18:30 | Spike in UK reports | BBC |
| 19:50 | Microsoft testing a configuration fix; affected servers restarted | BBC |
| About 20:00 | Reports down to about 77,000 | Al Jazeera |
Sources: BBC and Al Jazeera, 12 November 2026. Downdetector counts user reports, not confirmed users affected.
Why a failed health check spreads
In general, a health check is how a load balancer decides whether a server is fit to receive work. When servers fail the check, they are taken out of rotation, and the ones left take on more traffic. If that extra load pushes them past their own limits, they can fail too. Microsoft’s description of servers failing checks and straining the remainder fits that pattern, but the company has not said so, and the sources do not describe the root cause.
The user-facing symptoms were plain. Al Jazeera reports that some people said emails were not being sent or received, while others could not open their inboxes at all. Teams, Microsoft’s workplace messaging app, and Copilot were hit alongside Outlook, along with other Microsoft 365 services.
The sources leave several questions open. Microsoft’s own status updates are the only source for the cause, so everything about the fault is the company’s account. Neither report says how many customers were affected in total, because Downdetector counts reports and not users. Microsoft has not said why so many servers failed their health checks at once, whether any customer data was affected, or whether business customers will receive service credits.
The outage also shows how many tools sit behind one provider. A fault in one company’s infrastructure took mail, messaging and AI assistance offline together. The people who bear the cost are employers and staff who had no other route to the same tools. The reports so far describe a recovering service, not a finished fix, and neither mentions a post-incident review.
