Overview
- On Thursday, November 12, 2026, Microsoft confirmed a global disruption that is preventing many users from reaching Exchange Online (Outlook) and Microsoft Teams.
- Microsoft says an unusually large number of servers unexpectedly failed and are failing automated health checks, and investigators suspect a specific server‑integrity component is causing the faulty checks.
- Engineers have paused deployments and configuration changes, redistributed traffic, restarted affected servers, and are testing configuration workarounds to bypass the suspect component while preserving diagnostic telemetry.
- Downdetector recorded roughly 130,000 Outlook outage reports with U.S. users hardest hit and other reports from countries including Austria, and administrators are directed to incident IDs EX1550543 and MO1550821 in the Microsoft 365 Admin Center.
- The outage is affecting not only email and meetings but also services such as SharePoint Online, Microsoft Copilot and Defender XDR, which could force businesses to use backup communications and security controls until Microsoft completes its fixes.