Expired Certificate Causes Global Outage in Microsoft 365 Suite
Microsoft's Microsoft 365 suite experienced a global outage due to an expired certificate thumbprint within its core authentication configuration. The issue affected multiple services, including Exchange Online, Teams, SharePoint Online, OneDrive for Business, and Defender XDR.
The incident started on August 31, with users reporting delayed or failed mail, broken search, authentication errors, mailbox operation failures, and trouble reaching Exchange administration tools. Microsoft acknowledged the issue and attributed it to a configuration problem that stopped authentication components from deploying as expected.
The company took a cautious approach in fixing the issue, testing its remediation strategy on a portion of infrastructure before expanding it more widely. By September 1, the outage had entered its second day, with Microsoft stating that service availability was improving but not back to normal.