A widespread Microsoft Outlook outage left tens of thousands of people unable to send, receive or even open their email on Thursday, 12 November, with Microsoft Teams, Copilot and other Microsoft 365 services also hit. The disruption dragged on for more than five hours for many users.
Reports of problems with Outlook peaked at 138,058 on the tracking website Downdetector at about 1 p.m. US Eastern Time (7 p.m. in Nigeria), Reuters reported. By the evening, Outlook reports had fallen to around 34,500.
What went wrong in the Microsoft Outlook outage
Microsoft said the problems mainly affected Exchange Online, the service that powers business email in Microsoft 365. Early in the day, the company said a number of servers had become unexpectedly unavailable for the elevated load they were handling, according to Reuters. It added that users were having trouble reaching Exchange Online mailboxes through several connection methods in the Americas, the Associated Press reported via the Boston Globe.
Engineers tested a configuration change to redistribute traffic and restarted affected servers, Al Jazeera reported. The company’s Microsoft 365 Status account said it was “aggressively pursuing all pathways to reduce impact.” Microsoft has not yet given a full explanation of the root cause.
Who was affected
Users reported being unable to load inboxes or send and receive messages, and thousands also flagged problems with Teams. Microsoft said the issues could affect customers in any region, according to Al Jazeera, though its updates focused on users in the Americas.
The knock-on effects reached beyond Microsoft’s own apps. OpenAI and Anthropic both reported problems with tools that connect their AI assistants to Microsoft 365, Reuters said. US electric truck maker Workhorse Group postponed its third-quarter results from Thursday to 16 November, citing disruption from the outage.
Is Outlook working again?
By 6 p.m. Eastern Time, Microsoft said restored servers were stable, traffic was being moved to alternative routes, and the remaining servers were being brought back online. Microsoft warned that users “may experience a gradual recovery as their clients reconnect,” Reuters reported. Teams problems in North America had earlier been reported as restored.
Users still having trouble are advised to check the Microsoft 365 service status page and, where possible, use the Outlook web app or mobile app while services recover.
What happens next
The outage is the latest in a string of high-profile cloud failures. Last month, a separate Azure outage disrupted Microsoft’s productivity software and businesses around the world. Microsoft is expected to publish a post-incident report explaining what caused Thursday’s failure.
For more technology news, visit our Tech section.
Sources: Reuters, Associated Press/Boston Globe, Al Jazeera, ABC News.
