Microsoft 365 Outage Knocks Out Outlook, Teams and Copilot as Servers Go Offline

The problems began shortly after noon in the eastern United States, according to WGCU, and complaints on the outage tracker Downdetector passed 65,000 at one point. Users said they could not open mailboxes, send or receive email, view calendars or sign in to Microsoft 365. Microsoft first said the problem affected Exchange Online customers in the Americas, then warned that it could affect connectivity "for users in any region."

For companies, the damage comes from how many services failed together. Microsoft said Teams, SharePoint Online and Microsoft 365 Copilot were affected, as was Defender XDR, its security detection and response product. Organisations that rely on the suite could lose email, meetings, file sharing, their AI assistant and part of their security monitoring at once. TechCrunch reported that consumers also could not reach OneDrive storage or Office for the web.

Microsoft's explanation changed as the day went on. It first said it had found connectivity errors in the part of Exchange Online that handles user access requests, and that it was reviewing network logs to trace them. Later updates said infrastructure in several regions was under "elevated load". In a post on X for administrators who could not reach the Microsoft 365 admin centre, which was itself unreachable at times, the company said it was "redistributing connection traffic across our broader worldwide infrastructure to help balance the load." Its latest stated cause, that many servers had become unexpectedly unavailable, did not say why they failed.

The company said it had paused all deployments, was moving traffic away from the affected systems and was restarting servers. "We're aggressively pursuing all pathways to reduce impact," Microsoft said in one update. The admin centre lists the incident as a service degradation under reference EX1550543.

The extent of any disruption in the UAE had not been confirmed, although Microsoft's warning covered every region.

This is Microsoft 365's second major outage in about two months. In September an outage lasting several days hit the suite, including Outlook, and Microsoft blamed a "core authentication configuration" issue that stopped users from getting into the service.

Microsoft gave no time for full restoration in Thursday's updates. It told administrators to check the Microsoft 365 admin centre for progress on the incident.