MO1220495: Microsoft 365 suite Service Health Incident (Service Restored)

[365 Service Alert]

Users may be unable to access Microsoft 365 services.                                                                                                                                                                                                                                                       

Users may be unable to access Microsoft 365 services ID: MO1220495 Issue type: Incident Status Service Restored Impacted services Microsoft 365 suite Details Title: Users may be unable to access Microsoft 365 services User impact: Users may have been unable to access Microsoft 365 services, including Teams and Outlook. More info: As this issue was a result of a third-party ISP Autonomous System Number (ASN) routing configuration issue; the impact to Microsoft 365 services may have manifested in a multitude of ways. For example, some users may have been unable to access the services and portals altogether, whereas others may have seen impact more variable, such being intermittently unable to send or receive email. Final status: 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. Scope of impact: Your organization was affected by this event, and any of your users hosted in North America may have been impacted. Start time: Wednesday, January 21, 2026, at 4:10 PM UTC End time: Wednesday, January 21, 2026, at 5:10 PM UTC Root cause: A third-party ISP ASN routing configuration issue caused impact to downstream services, such as Microsoft 365. Next steps: - We're carefully monitoring our managed service environment to ensure the issue doesn't reoccur, and we're reviewing our service resilience practices to identify any necessary improvements so we can reduce the downtime associated with these types of ISP-dependent issues in the future. This is the final update for the event. Is this message helpful? Did you find this email helpful? Yes No To customize what’s included in this email, who gets it, or to unsubscribe, set your Service health preferences. If you are receiving this email because your Admin added you as a recipient, please contact your Admin to unsubscribe. Privacy Statement Microsoft Corporation, One Microsoft Way, ​Redmond, WA 98052​