Microsoft 365 outage disrupts Outlook, Teams and connected AI tools

Microsoft 365 connectivity problems disrupted Outlook and Teams on Nov. 12, with Microsoft saying users in the Americas were having trouble reaching Exchange Online mailboxes and that the issue could affect service connectivity in any region. Reuters reported that Downdetector logged tens of thousands of user reports, while Microsoft worked to shift traffic and repair affected infrastructure.

• Downdetector had logged more than 129,000 Outlook problem reports by 1:09 p.m. ET, Variety reported; these were reports, not a verified count of people affected.
• Microsoft said elevated load across multiple regions was likely contributing to connectivity errors.
• OpenAI and Anthropic reported problems involving their Microsoft 365 connectors, according to Reuters.

Microsoft 365 outage reports and user impact

Reuters, in reporting carried by CNA, said Downdetector recorded about 38,000 reports involving Microsoft 365 and roughly 4,500 involving Teams. Downdetector aggregates reports from multiple sources, so its figures indicate reported problems rather than the number of unique affected users. Variety said Outlook reports began rising at about 12:39 p.m. ET and had passed 129,000 by 1:09 p.m. ET.

What Microsoft said it was doing

Microsoft said users were experiencing trouble accessing Exchange Online mailboxes through multiple connection methods in the Americas, and warned that Microsoft 365 connectivity could be affected in any region. It later attributed the errors, in part, to elevated load on a portion of infrastructure across multiple regions. Variety reported that Microsoft was redistributing connection traffic across its worldwide infrastructure and reviewing an unexpected increase in a specific type of service traffic to determine whether it was contributing to the load.

Reuters reported that Microsoft paused deployments, moved additional traffic away from affected infrastructure and restarted affected servers. The company described these measures as efforts to reduce the impact and restore capacity. The reports did not establish the eventual cause of the disruption or when all affected services returned to normal.

What the outage meant for connected services

The disruption reached beyond Microsoft’s own products. Reuters said OpenAI was investigating a Microsoft connector issue in which new connections could break and tools might not work as expected. Anthropic said an upstream provider issue was affecting its Microsoft 365 connector. These reports describe problems for services connected to Microsoft 365, rather than a separate outage affecting all of either company’s products.

Microsoft had said earlier on Nov. 12 that a Teams disruption affecting North American users was fixed and its impact fully resolved. Its later warning that Microsoft 365 connectivity could be affected in any region referred to a broader connectivity issue. The available updates identified elevated infrastructure load as a likely contributor; Microsoft was still reviewing whether an increase in a particular type of traffic played a role.