Overview
- Microsoft acknowledged on Thursday that users experienced access problems to Exchange Online/Outlook and other Microsoft services while Downdetector recorded spikes of tens of thousands of user reports.
- The company initially pointed to elevated infrastructure load and later revised its diagnosis to servers that were unexpectedly unavailable, which it said overloaded systems.
- To mitigate the outage Microsoft redistributed traffic across its global network, suspended updates, redirected access away from affected infrastructure and restarted problematic servers.
- The incident and updates were posted in the Microsoft 365 admin center under incident codes EX1550543 and MO1550821, and Microsoft reported services were restored roughly an hour after first public acknowledgements.
- Because Exchange Online and Microsoft 365 host core email and productivity tools for many organizations, the brief disruption interrupted work for users and underscores how root causes can change as engineers investigate.