Seattle -- Microsoft users encountered an authentication error with Office 365 systems, including Outlook mail, Microsoft Teams, Teams Live Events and Office.com services. A Tweet at 11pm 9/28 from Microsoft 365 Status stated "We’ve confirmed that the residual issue has been addressed and the incident has been resolved. Any users still experiencing impact should be mitigated shortly.

"Starting at approximately 21:25 UTC, a subset of customers in the Azure Public and Azure Government cloud may encounter errors performing authentication operations for a number of Microsoft/Azure services, including access to the Azure Portals," the company said in a status post. In another post, the company said users would be unable to access Office.com, Outlook.com, Teams, Power Platform, and Dynamics365.

By 00:40 UTC, Microsoft said it was seeing improvement across multiple services. "We're continuing to see significant improvement for affected services and most users should be experiencing relief," Microsoft added at 1:20 UTC.

At 4:00 UTC, the company said the issue was resolved. "We've confirmed that the residual issue has been addressed and the incident has been resolved. Any users still experiencing impact should be mitigated shortly," it said.