User impact: Admins may be unable to deploy custom add-ins from the Microsoft 365 admin center and users can’t access add-ins.

More info: Admins see an error stating “Learn more about eligibility requirements”.

Users also report being unable to access deployed add-ins in relevant services such as Exchange Online. Affected add-ins we’ve validated include, but may not be limited to, the following:

– My Templates add-in
– Salesforce add-ins
– Viva Insights add-ins

Current status: We’ve merged communications discussing impact to deployment or access to custom add-ins into a single communication to provide more streamlined and consistent feedback on our mitigation actions. We’ve updated the “Title”, “User impact”, “Scope of impact”,”Start time”, and “Root cause” fields of this communication to reflect this change. We’ve deployed a code fix designed to correct the offending code mismatch in our authentication infrastructure to a subset of our service infrastructure, and we’re testing for remediation with a subset of affected users prior to initiating a wider deployment. We aim to provide a timeline to wider deployment at the time of our next scheduled update.

Scope of impact: Some admins may be unable deploy custom add-ins from the Microsoft 365 admin center and all users may be unable to access deployed add-ins. This information may be updated as our investigation continues.

Start time: Wednesday, January 21, 2026, at 10:27 AM UTC

Root cause: A recent service change designed to enforce stricter authentication requirements blocked admins from deploying custom add-ins from the Microsoft 365 admin center and blocked user authentication requests from completing.

Next update by: Friday, March 20, 2026, at 8:30 PM UTC