Microsoft Outlook Outage: Microsoft 365 Down for 130,000+ Users as Teams and Copilot Fail

The Microsoft Outlook outage began on Thursday, November 12, 2026, when users around the world suddenly found they could not open their inboxes, send email, or join Teams calls. Within an hour the disruption had spread to 74 countries and territories, according to outage tracker Downdetector, and reports of problems with Outlook peaked at more than 138,000. Microsoft says a portion of its infrastructure came under elevated load after a number of servers unexpectedly went offline — and as of Friday morning in India, the company has still not declared the outage fully fixed.

Microsoft Outlook Outage: What Happened and When

The trouble started at about 11:17am Eastern Time on Thursday (9:47pm IST), when Microsoft opened incident EX1550543 for Exchange Online, the cloud email service behind business Outlook accounts. Users reported they could not reach their mailboxes through Outlook on the web, the desktop app, or mobile connections, and email delivery began to slow. Just over two hours later, at 1:26pm ET, Microsoft opened a second, wider advisory, MO1550821, covering every service that depends on Exchange Online — including Teams, SharePoint Online, Microsoft 365 Copilot and Defender XDR. Reports on Downdetector surged through the US workday, peaking at 138,058 Outlook complaints at around 1pm ET, with more than 38,000 reports for Microsoft 365 and about 4,500 for Teams at the same time. A separate Teams outage in North America, tracked as TM1550488, had already been resolved earlier in the day, between 2:45pm and 3:53pm ET, but the wider failure kept spreading.

How Many Users Were Affected by the Microsoft 365 Outage?

The scale of the Microsoft Outlook outage was global. Downdetector's map showed users affected across the Americas, Europe, Asia and Africa, with the United States and the United Kingdom worst hit. Microsoft's own status page warned that users may be unable to connect to multiple Microsoft 365 services, and the disruption even reached beyond Microsoft's own apps: Reuters reported that the outage hit connectors used by the AI services of OpenAI and Anthropic. Microsoft also said multiple Purview services were impacted, including authorization, auto-labelling, data loss prevention, communication compliance and data classification.

• Outlook reports peaked at 138,058 on Downdetector at around 1pm ET on Thursday.
• More than 130,000 users reported Outlook problems shortly after 1pm ET; about 37,000 were still reporting issues by 6pm ET.
• Over 38,000 reports for Microsoft 365 and about 4,500 for Teams at the peak.
• Users in 74 countries and territories were affected, according to Downdetector.
• Outlook, Teams, Copilot, SharePoint Online, OneDrive and Defender XDR were all listed as potentially affected.

What Caused the Microsoft Outlook Outage?

Microsoft has not published a full root cause, and says the answer will usually appear in a post-incident report in the Microsoft 365 admin centre days later. What the company has said so far is that a number of servers became unexpectedly unavailable after failing automated health checks, which piled extra load onto the remaining infrastructure and caused connectivity errors. Microsoft stressed that the problem was not caused by a surge in demand. The company also said it has no indication of a cyber attack behind the outage, and Australia's Home Affairs Minister Tony Burke said Microsoft did not believe the disruption was caused by a cyber event. To bring servers back, Microsoft validated an alternative method for the automated health checks and began applying it more broadly, while temporarily limiting which types of traffic can reach the affected infrastructure in some locations.

Is the Microsoft Outlook Outage Fixed Yet?

Not fully — and that is the key point as of Friday morning, November 13. Microsoft has begun returning affected servers to service, and said the restored servers remain stable so far, with traffic being shifted to alternative routes. But the recovery has hit complications: the company found that some servers became unresponsive again once they started receiving traffic, and it is still analysing diagnostic data to work out what is triggering that behaviour. By Thursday evening in the US, reports had fallen sharply — Outlook complaints were down to about 34,490 by 6pm ET and Microsoft 365 reports to around 13,000 by 5:47pm ET — but Microsoft was still working to return affected servers to service and had observed only limited recovery. The company's latest update, at 02:14 UK time on Friday, said it was applying infrastructure capacity improvements where possible, with the next update due by 03:00 UTC. Email delivery may still be delayed, and users should expect intermittent service until Microsoft confirms the systems are operating normally.

What to Do If Outlook Is Still Down

If your inbox still will not load, first check Microsoft's official service status page or the Microsoft 365 Status account on X for the latest update — the incident numbers to look for are EX1550543 for Exchange Online and MO1550821 for the wider Microsoft 365 advisory. Try Outlook on the web if the desktop app fails, or the other way round, since different connection methods were affected at different times. Avoid repeatedly resending the same email, as delivery may simply be delayed rather than lost, and hold off on password resets — this is a server-side outage, not an account problem. Workplace admins can follow the incident numbers in the Microsoft 365 admin centre, where Microsoft posts its updates first. For most users, the practical answer is to wait for Microsoft's all-clear rather than reinstalling or reconfiguring anything.