Microsoft 365 Partial Outage on September 28, 2020 (Resolved)

Users with email and services hosted on Microsoft 365 may be experiencing issues.

7:20 p.m. -- Microsoft has confirmed via their monitoring that the majority of services have recovered for most customers. However, they continue to see a small subset of customers whose tenants are located in North America region who are still impacted. They're now investigating mitigation steps for those customers who are still affected.

5:11 p.m. -- Microsoft has determined that a specific portion of the infrastructure is not processing authentication requests in a timely manner. They're pursuing mitigation steps for this issue. In parallel, They're rerouting traffic to alternate systems to provide further relief to the affected users.

4:03 p.m. -- Microsoft has identified that reverting the recent change did not alleviate impact to Microsoft services as expected. They are working to explore additional options for mitigation.

3:55 p.m. -- Microsoft has completed reverting the change which was likely causing impact and are monitoring the environment to ensure that services are recovering.

3:45 p.m. -- Users would be unable to access, Microsoft Teams including Teams Live Events, and Existing customer sessions are not impacted and any user who is logged in to an existing session would be able to continue their sessions.

3:29 p.m. -- Existing sessions do not appear to be affected. Affected users are encouraged to keep existing sessions going and to avoid re-authenticating to Microsoft 365 services.

3:20 p.m. -- User Impact: Users may be unable to access multiple Microsoft 365 services.

More info: Any Microsoft 365 service that leverages Azure Active Directory (AAD) authentication may be impacted by this issue.

Current status: Microsoft has identified and are reverting a recent change to the service which may be causing or contributing to impact.

Scope of impact: Any user may experience access problems for Microsoft 365 services.

Updates can be found at If you have additional questions or issues with services, please contact IT Services at or (310) 267-HELP (4357).