Windows
Teams sign-in failed until Microsoft Authenticator was reset on the new phone
A seasonal external user could not complete sign-in for Teams after moving to a new phone. Support reset Microsoft Authenticator and reconnected it on the new phone, and sign-in was confirmed to work normally.
Killed once by someone from XL.net, on 2026-01-06.
Affects
Apps
- Microsoft Authenticator
- Microsoft Teams
Hardware
- phone
What you see
- Sign-in errors when trying to use Teams as an external user
- Authentication would not complete after the user changed phones
Why it happens
Likely Suspected stale Microsoft Authenticator enrollment after a phone change.
When it shows up
A user changes phones and can no longer finish Microsoft 365 or Teams sign-in with Microsoft Authenticator
You are in this case if:
- Microsoft Authenticator is part of the sign-in flow
- The user recently moved to a new phone
1 fix below
The steps that killed it
The steps are behind a quick check
There are two ways in and both take a few seconds. Signing in opens the steps on every bug page; so does reading the picture.
Or answer this
Drawing a picture for you.
Can't read it? Sign in instead.
Someone from XL.net killed this on a Windows computer on 2026-01-06. It is written up from that one repair, so it cites no outside page.