Some users may have been unable to sign-in to the Microsoft Teams iOS application

Title: Some users may have been unable to sign-in to the Microsoft Teams iOS application
User impact: Users may have been unable to sign-in to the Microsoft Teams iOS application.
More info: This issue was specific to some users that weren’t already signed in to the Microsoft Teams iOS application and whose SkypeTokens expired. Furthermore, users whose SkypeTokens expired while being signed in to the service may have been prompted for re-authentication, and subsequently may have been unable to sign in to the Microsoft Teams iOS application.
Final status: We identified that a section of authentication infrastructure, responsible for regulating sign-in for the Microsoft Teams iOS application, was unexpectedly operating below acceptable thresholds and causing impact. We observed our automated recovery systems return the service to expected performance levels, and subsequently confirmed following a monitoring period that impact has been remediated.
Scope of impact: Impact was specific to some users who were served through the affected infrastructure.
Start time: Monday, October 2, 2023, at 11:21 AM UTC
End time: Monday, October 2, 2023, at 12:42 PM UTC
Root cause: A section of authentication infrastructure, responsible for regulating sign-in for the Microsoft Teams iOS application, was unexpectedly operating below acceptable thresholds and causing impact.
Next steps:
– We’re reviewing our Microsoft Teams iOS application sign-in authentication procedures to reduce or avoid similar impact in the future.
This is the final update for the event.