Microsoft Authenticator log in loop

This usually happens after changing phones when the sign-in approval is still tied to the old device, or when the account was not fully restored on the new phone.

Try this in order:

1. Check whether the prompt is going to the old phone Microsoft Authenticator can send the push notification to the device where the app was last used. If the old phone is still available, open Authenticator there and approve the sign-in.
2. Use another verification method if it is offered If the sign-in page shows another method such as SMS, use that to get back in.
3. If the account was restored to the new phone, open the account tile in Authenticator and sign in again For work or school accounts, seeing “Sign in to add your account” after restore is expected. Open that account in Authenticator and complete sign-in again.
4. Remove old phone details and add the new phone In the security verification settings, delete the old phone entry, then add the new phone as a sign-in method so prompts go to the correct device.
5. If notifications are not arriving on the new phone, check the app and device settings
   • Switch between mobile data and Wi-Fi
   • Make sure Airplane mode is off
   • Update Authenticator to the latest version
   • In Authenticator, go to Settings and turn off battery optimization
   • In Settings > Notification Settings, make sure Show notifications is on
   • Verify device Date & time are correct
   • If using VPN, disconnect and test again
6. If none of the above works for a work or school account, contact the organization’s IT admin After a phone change, if the old Authenticator setup is no longer usable and no alternate method works, the MFA methods may need to be reset so registration can be completed again.

For the number prompt itself: number matching on Android can appear on the sign-in screen, but in a browser the notification must be tapped to enter the number and approve the sign-in.

Also, never read Authenticator codes to anyone over phone or text. Microsoft warns that attackers commonly ask for these codes to gain access.

References:

• Microsoft Authenticator FAQs | Microsoft Support
• Transfer Microsoft Authenticator account entries to a new phone
• Use a screen reader to set up and troubleshoot multifactor authentication | Microsoft Support
• Troubleshoot problems with Microsoft Authenticator | Microsoft Support
• How number matching works in MFA push notifications for Authenticator - Authentication methods policy