Microsoft outage disrupts Outlook, Teams for thousands, persists over five hours

Microsoft 365, including Outlook and Teams, experienced a multi-hour outage on Thursday, Nov 12, impacting thousands of users across regions. The disruption also affected connectors used by OpenAI’s and Anthropic’s AI services.

By 6 p.m. ET (7 a.m. Singapore time on Friday), Microsoft said it was still working to restore affected servers, noting limited recovery as users gradually reconnected. Downdetector reported that outage reports for Outlook peaked at 138,058 around 1 p.m. ET and fell to about 34,490 by evening, later dropping to roughly 13,000. Reports of Teams issues stood at 763 at the same time.

"We are aware and investigating reports of users experiencing issues with Microsoft 365 services, primarily issues with Exchange Online," a Microsoft spokesperson said.

"As capacity is restored, users may experience a gradual recovery as their clients reconnect," Microsoft added.

The company attributed the problem to several servers becoming unexpectedly unavailable under elevated load, rather than a traffic surge. It indicated that restored servers remained stable and that traffic was being shifted to alternate routes while remaining servers were brought back online.

OpenAI confirmed it was investigating a problem with Microsoft connectors that could break new connections, and Anthropic identified an issue with an upstream provider affecting its Microsoft 365 connector.

The outage prompted electric-truck maker Workhorse Group to postpone its third-quarter earnings release to Nov 16, citing business disruptions caused by the global Microsoft outage.