Tens of thousands of users reported outages for Microsoft Outlook and Microsoft 365 on Thursday, January 22, 2026, experiencing difficulties sending emails and accessing various services. The issues began in the afternoon, with users encountering a "451 4.3.2 temporary server issue" error message when attempting to send or receive emails. Microsoft attributed the widespread problems to a failure in "service infrastructure in the North America region" that was not processing traffic as anticipated.
While Microsoft initially stated that the affected infrastructure had been restored to a healthy state, further load balancing was necessary to address persistent impacts. The company indicated that additional actions were being implemented to redirect traffic to healthy sections of their infrastructure for a more resilient recovery. Microsoft 365 and Outlook are utilized by millions globally and by numerous businesses.