Microsoft 365 and Teams Outages Due to Infrastructure Issues
Breach & Incident Intelligence · 2 sources · Updated 4mo ago · First seen Dec 19, 2025

Microsoft Teams experienced widespread outages, with users across the United States, Europe, and other regions reporting delays in sending messages and problems with other service functions. Microsoft acknowledged the issue publicly, stating that they were investigating the cause and observing signs of recovery, but did not initially provide a root cause or timeline for full restoration. The outage disrupted communication for many organizations relying on Teams for collaboration and messaging.
Separately, a significant outage affected Microsoft 365 services—including Teams, Outlook, OneDrive, and the Copilot AI assistant—in Japan and China. This disruption was traced to a critical routing misconfiguration in Microsoft's infrastructure, which isolated healthy systems and led to intermittent login failures, degraded performance, and app loading errors. Microsoft confirmed that the incident was not the result of a cyberattack and reported that engineers had rebalanced traffic to restore service, with no data loss or security breaches identified. The outages caused notable business disruption in the affected regions, particularly for organizations dependent on Microsoft’s cloud ecosystem for daily operations.


