Microsoft 365 users ran into widespread problems on Thursday afternoon, November 12, 2026, with Outlook taking the hardest hit. Outage reports on Downdetector started climbing after about 12:21 p.m. ET, and Outlook problem reports peaked at nearly 130,000 around 1 p.m. to 1:15 p.m. ET. Downdetector counts user reports rather than unique users, so the real number of people affected could be different. Many users said they couldn't send or receive emails or couldn't even load their inboxes. Thousands more reported trouble with Teams and Copilot, and Microsoft 365 as a whole peaked at more than 48,000 reports.

Microsoft acknowledged a service degradation and said it was investigating problems with access to Exchange Online mailboxes in the Americas, later warning that users in other regions could be affected too. The company said a portion of its infrastructure was dealing with elevated traffic and strain, and it moved traffic for some services off that infrastructure to reduce the load. "We're aggressively pursuing all pathways to reduce impact," the Microsoft 365 Status account wrote. The disruption also reached connectors used by OpenAI's and Anthropic's AI services, which both said they were looking into related issues. In the latest reports I found, Microsoft was still working to restore service and had not given a full explanation of the root cause.