**Summary of the Microsoft 365 Outage (January 22-23, 2026):**
**What Happened:**
Microsoft 365 services experienced a significant outage beginning around 11:40 a.m. Pacific time on January 22, 2026.[2] The disruption impacted multiple critical services including Outlook, Teams, Microsoft Defender, and Microsoft Purview, with some services remaining affected into January 23.[1][4]
**Impact and Scale:**
Downdetector tracked over 11,000 reports for Outlook and more than 14,000 reports across Microsoft 365 services.[4] The outage affected primarily North America but users in the UK, Germany, France, Australia, India, Japan, and Brazil also reported issues.[4] Users encountered the “451 4.3.2 Temporary server error” when attempting to send or receive emails.[4]
**Root Cause:**
Microsoft identified a portion of service infrastructure in North America that was not processing traffic correctly, affecting load balancing and service availability.[2][4] An intended mitigation effort caused problems elsewhere in the company’s infrastructure.[2]
**Recovery Status:**
Microsoft confirmed the underlying infrastructure had been restored to a “healthy state,” though some services required further load balancing.[4] Consumer products returned to normal operation first, with gradual restoration of 365 services.[2]
