Key facts
- Microsoft is addressing a multi-day outage affecting Outlook and other Microsoft 365 services.
- The outage is attributed to an issue with a core authentication configuration.
- Users experienced email delays, sending/receiving failures, and authentication problems.
- Microsoft has implemented mitigation actions and reports improving service availability.
- Services including SharePoint, Copilot, Teams, and Defender XDR were also affected.
Microsoft's efforts to resolve a multi-day outage impacting Outlook email and other Microsoft 365 services are continuing into their second day. The company reported significant progress on Monday after an issue with its Exchange Online service caused email delays, sending and receiving failures, and authentication problems for users. As of Tuesday, the issues are not fully resolved, with Microsoft stating that mitigation actions are progressing and service availability is improving. The problem was attributed to a misconfiguration in a core authentication component used across multiple Microsoft 365 services, preventing authentication components from deploying as expected. Services affected include Outlook, SharePoint, Copilot, Teams, Purview, Defender XDR, the Microsoft 365 Admin Center, and Universal Print. Microsoft initially focused on rolling out gradual recovery for mail flow and later saw improvements in search functionality. The company is now in a phase of extended monitoring to ensure complete resolution.