Microsoft 365, Outlook, and Teams experienced a significant service disruption on Nov. 12, affecting thousands of users across the United States and globally, according to a recent report by Security Affairs.
The outage, which began at 1:26 p.m. ET, impacted critical platforms including Exchange Online, SharePoint Online, Microsoft Defender XDR and Copilot. Downdetector recorded over 97,000 incidents for Outlook alone. While Microsoft initially attributed the instability to heavy workloads, the company later clarified that the failure stemmed from servers unexpectedly going offline, which strained the remaining infrastructure. The disruption extended beyond internal tools, breaking connectors used by OpenAI and Anthropic to access Microsoft 365 accounts.
This prevented these AI services from retrieving user data or interacting with inboxes. In response, Microsoft paused all deployments and redistributed traffic across its global network to restore capacity. A separate, smaller incident earlier that morning also hindered Teams messaging in North and South America due to resource contention. IT administrators were advised to monitor the Microsoft 365 admin center for status updates as the company worked to bring the affected servers back online and stabilize the environment for global users.
Source: Security Affairs
