Microsoft reports service disruptions affecting Outlook and Teams

Microsoft said users in the Americas were experiencing problems accessing Exchange Online mailboxes through multiple connection methods, and users in North America reported difficulties with Microsoft Teams functionality. The company attributed the mailbox issue to a number of servers being unexpectedly unavailable, which strained the remaining infrastructure.

"We determined the elevated load isn't driven by an increase in traffic, but by a number of servers being unexpectedly unavailable; straining the remaining infrastructure," Microsoft said.

The firm added that it had not identified a recent change linked to the outage, but suspected a failed health-check component responsible for processing server health. It said steps were taken to prevent further servers from being impacted while the affected servers were being restored.

"We've taken steps to prevent additional servers from being impacted while we work to return the affected servers to service," the company stated.

For Teams, Microsoft reported that mitigative actions had restored service health and functionality.

"Our mitigative actions have successfully restored service health and functionality," the company said.

Downdetector, an outage-monitoring service, also logged problems with Teams, Outlook and other Microsoft products on Thursday. Microsoft confirmed that the Exchange Online issue could affect Microsoft 365 connectivity for users in any region and said it had paused deployments, redirected traffic and begun restarting affected servers to reduce impact.

"We're aggressively pursuing all pathways to reduce impact. We've paused all deployments, we're moving additional traffic off the affected infrastructure, and we're restarting affected servers to return them to service," Microsoft added.

The situation remains under investigation, and further updates are expected.