Microsoft reroutes traffic as Outlook and Microsoft 365 outage hits users worldwide

Microsoft is diverting traffic around servers that failed during automated system checks after a worldwide disruption hit its cloud services, including the Outlook email service, on 12 November.

The company first reported problems with Exchange mailboxes in the United States, then said the disruption could affect users of Microsoft 365 worldwide. Microsoft said part of its infrastructure was under "increased load", which was "probably contributing to the connection problems", and that a number of servers were "unexpectedly unavailable" after a fault during automated system checks. The company said it was also aware of users in North and South America experiencing difficulties accessing their Exchange Online mailboxes across various connection methods.

Outage-tracking platform Downdetector recorded almost 130,000 reports of Outlook problems at around 19:00 CET, falling to about 50,000 by 22:30. Thousands of reports were also logged for the Microsoft Teams communications service and the Copilot AI assistant, both part of Microsoft 365.

The Microsoft 365 Status account on X said the company was pursuing every option at full speed to reduce the impact. How long the disruption would last remained unclear.