On November 12, 2026, an outage disrupted several Microsoft 365 cloud services. Users in multiple regions reported trouble accessing Outlook, Exchange Online, Teams, OneDrive and other products, including problems sending or receiving email and opening cloud files. At one point, Downdetector had received nearly 130,000 reports about Outlook.
Microsoft initially investigated problems affecting access to Exchange Online mailboxes in the Americas. It later said users anywhere in the world could be affected. Its service-status information listed Exchange Online, Microsoft Teams, SharePoint Online, Microsoft 365 Copilot, Microsoft Defender XDR, Microsoft Planner and Microsoft To Do among the affected services. Some OneDrive users also reported access problems.
Microsoft said unusually high load on parts of its infrastructure caused connection errors. Its investigation found that many servers had unexpectedly become unavailable after failing automated health checks, increasing the load on those still running. The company was investigating why the checks failed and reviewing recent configuration changes that it said might be related; it had not established a definitive cause.
To restore capacity, Microsoft paused deployments and configuration changes, adjusted how connection traffic was distributed across its global infrastructure and began restarting affected servers. By 5 a.m. Beijing time on November 13, it had verified an alternative health-check method on some affected servers and begun extending it more widely. It was also preparing a mechanism to detect and restart unresponsive servers automatically.
Some administrators could not access the Microsoft 365 admin center. Microsoft advised them to check its public service-status page for updates.
