Microsoft suffered a widespread outage on Thursday that disrupted access to Outlook email and multiple other Microsoft 365 services for users across regions.

Reports of problems with Outlook peaked at nearly 130,000 on Downdetector shortly after 1 p.m. ET. Similar issues affected Teams, SharePoint Online, Copilot, and Defender XDR. The company tracked the events under incident IDs including EX1550543 for Exchange Online and MO1550821 for broader services.

Microsoft stated that a number of servers became unexpectedly unavailable after failing automated health checks. This situation created elevated load on the remaining infrastructure and contributed to connectivity errors. The outage was not attributed to increased traffic or a cyberattack.

The incident began with reports of issues accessing Exchange Online mailboxes in the Americas around 11 a.m. ET and expanded to affect users in any region. Microsoft posted updates on its status page and social media throughout the day, noting steps to shift traffic to alternate routes and return affected servers to service.

By early evening, the number of user reports on Downdetector had declined significantly from the peak, though thousands continued to experience problems. Microsoft indicated that some servers had returned to service and remained stable, while it pursued additional recovery measures including configuration adjustments.

The outage impacted productivity for businesses and individuals reliant on the company's cloud-based tools. Microsoft has not provided a specific root cause or timeline for full restoration as of its latest updates.