Authenticator App Sign-In Loop

Braden Michael Joseph Cook 0 Reputation points
2026-08-21T13:33:06.73+00:00

Upgrading my phone caused me to become signed out of my account on the Authenticator app. When I try to login to the app, it keeps saying that it’s having trouble verifying my account and is asking me to approve a request from the app or use a verification code, neither of which I can do because they require using the app that I am trying to login to. I was given the error code 500121, in case that’s helpful. How can I fix this and log into the Authenticator app?

Microsoft Security | Microsoft Authenticator

1 answer

Sort by: Most helpful
Most helpful Newest Oldest
  1. Braden Michael Joseph Cook 0 Reputation points
    2026-08-21T19:04:38.6+00:00

    I was able to go to my organization’s IT department to help get it fixed, but basically I removed my account from the app and then added it back to the app by signing back in manually. I’m not sure if I actually needed IT’s help or not to do this, but if the account isn’t a personal one then I would have to suggest going to them in case issues arise with adding the account back to the app in some way.

    Was this answer helpful?

    0 comments

Your answer

Answers can be marked as 'Accepted' by the question author and 'Recommended' by moderators, which helps users know the answer solved the author's problem.