Overview
- Users around the world reported problems with Outlook, Teams and Exchange Online, and Downdetector logged more than 130,000 reports for Outlook on Nov. 12.
- Microsoft posted incident EX1550543 in the Microsoft 365 admin center and said it was investigating Exchange Online mailbox access issues that showed up across multiple connection methods in the Americas.
- The company said parts of its infrastructure were experiencing high load, a condition it linked to the connectivity errors that also affected Teams, OneDrive, Copilot, Xbox and some enterprise security tools.
- Microsoft reported progressive restorations on Nov. 12 with email access returning for many users while engineers continue monitoring and applying fixes.
- The outage disrupted business communications and third‑party integrations such as OpenAI and Anthropic connectors, and follows a CISA alert earlier in the week about an Outlook vulnerability Microsoft said it fixed on Nov. 10.