Microsoft Teams, Exchange and more went down for four hours on Monday

Microsoft’s communications app was experiencing issues worldwide.

Microsoft Teams went down for around four hours on Monday, alongside Azure and other Microsoft 365 services. Microsoft blamed the issues on “a recent change to an authentication system” took some Microsoft 365 services down. A roll back to the change took longer than Microsoft expected, with the company confirming at 12:35AM ET that “impact has been largely mitigated.”

The issues started around 3:30PM ET, and Microsoft quickly confirmed they were affecting users worldwide. This is the first major Microsoft Teams outage since the service went down back in September, alongside other Microsoft 365 services like Office 365 and Outlook. Microsoft also blamed its previous outage on a configuration change.