I'm having a strange issue with enrolling any M365 account into the Microsoft Authenticator app. I haven't made any changes to our MFA setup in weeks; it's been running smoothly until this problem popped up suddenly yesterday.
My configuration includes a Conditional Access Policy that requires MFA for all users across all resources. The only authentication methods enabled in Entra's settings are MS Authenticator and QR Code for all users.
However, when I try to use the MS Auth app on my phone and scan the QR code for MFA setup, I get an error saying: 'Unable to add the account. Unexpected error. Please contact your local IT administrator to resolve the problem.'
Interestingly, I found out that if I use a different phone with the same account, I have no issues. I reset the MFA on this account twice and tried another device (a Samsung S8), and everything worked fine. The device I'm currently using is a Samsung S21FE. Any help resolving this would be appreciated, as I haven't found anyone else facing this specific issue.
4 Answers
Have you checked the Entra sign-in logs? They might provide some insights into what's going wrong. Sometimes, the logs show specific errors related to the phone or setup.
From what you've described, it seems you're trying to enroll the Authenticator incorrectly. The QR Code Login is meant to be used after the app is already set up. Follow the standard MFA setup flow to enroll the Authenticator first, and then the QR Code Login option will work post-setup.
It looks like you might be trying to use the QR Code for login instead of enrolling your Authenticator app. Make sure to first set up the Authenticator app before using the QR Code Login feature. Otherwise, it won't work properly!
Ah, got it! I activated the QR Code Login after encountering the issue, but I'll disable it as you suggest and try again.
Double-check that your legacy MFA settings are disabled, and ensure you have the current authentication methods selected. You might want to enable Software OAUTH, which allows registering and using various authenticator apps, including Microsoft Authenticator.
Thanks for the tip! I did complete the migration, so only the latest methods are active. I’ll look into Software OAUTH, too. Just to clarify, does that include other apps like Authy or Google Authenticator?
I checked the logs and saw some sign-in errors, which led me to think my phone might be the problem. It sounds like Android devices can be finicky sometimes, especially with the MFA setup. I may need to clear the app cache and try again.