Overview
- On Thursday, November 12, users and monitoring sites reported widespread failures that blocked access to Exchange Online/Outlook and other Microsoft 365 services.
- Microsoft logged the problem as incident EX1550543 (also referencing MO1550821) and posted updates in the Microsoft 365 admin center and official status channels.
- The company attributed the outages to elevated load combined with unexpected server unavailability and has begun redistributing connection traffic across its global infrastructure.
- Third‑party monitors recorded large spikes in user reports, including Downdetector data showing a sharp surge of reports in the United States, while Microsoft has not given an overall affected‑user count or a recovery ETA.
- The outage has disrupted email, collaboration and AI tools such as Outlook, Teams, OneDrive and Copilot, and businesses should follow Microsoft’s official status pages and incident codes for real‑time updates.