Microsoft 365 and Teams Outages Due to Infrastructure Issues
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.
Timeline
Dec 19, 2025
Microsoft confirms Teams outage and opens investigation
Microsoft publicly acknowledged the Teams incident on X, saying it was investigating the disruption, identifying affected scenarios, and reviewing telemetry that showed some signs of recovery. The company said further updates would follow as it worked to determine the root cause.
Dec 19, 2025
Microsoft Teams outage begins across the US and Europe
A separate widespread Microsoft Teams outage started at 14:30 ET, affecting users in multiple regions including the United States and Europe. Users reported problems such as delayed message delivery.
Dec 18, 2025
Microsoft mitigates Asia-Pacific outage by rebalancing traffic
Microsoft engineers responded to the Asia-Pacific service disruption by rebalancing traffic across redundant systems, leading to partial recovery within hours. The company said there was no evidence of a cyberattack, data loss, or security breach and continued monitoring pending full restoration.
Dec 18, 2025
Microsoft 365 and Copilot outage hits Japan and China
A major Microsoft 365 outage began around 00:00 UTC, disrupting Outlook, Teams, OneDrive, and Copilot for users in Japan and China. Microsoft said the incident was limited to the Asia-Pacific region and caused login failures, degraded performance, and app loading errors.
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