Microsoft 365 Service Degradation, Potential Impact to Teams and Outlook

We've determined this issue was a result of a third-party ISP Autonomous System Number (ASN) routing configuration issue, and we've identified that the third-party has taken action to remediate the impact to downstream services, such as Microsoft 365, and we've confirmed the issue is no longer occurring.

Microsoft’s investigation currently suggests the impact may be associated with a possible third-party networking issue. They are continuing to review the health of the Microsoft managed service environment to determine whether mitigation is required and to ensure services are healthy.

Latest Microsoft update: January 21, 2026, 12:36 PM EST

Issue ID (Microsoft): MO1220495

Microsoft continues to investigate the Microsoft 365 service degradation. Reports indicate ongoing impact for some users, primarily in North America, and may include Microsoft Teams and Outlook (Exchange Online).

Microsoft’s latest notes indicate they are reviewing regional network health and service telemetry to determine whether connectivity issues within Microsoft’s managed environment are contributing to the impact.

Latest Microsoft update: January 21, 2026, 12:15 PM EST

Issue ID (Microsoft): MO1220495

Microsoft has reported a service degradation affecting Microsoft 365. They are investigating a potential issue that may impact services, including Microsoft Teams and Outlook.

Last updated by Microsoft: January 21, 2026, 12:07 PM EST.

We will share updates as Microsoft provides more information.