Unable to authenticate Microsoft Authenticator login, endless loop

Follow these steps in simple terms, starting from what still works (the laptop):

1. Stay signed in on the laptop
   Do not sign out or clear cookies on the laptop browser or apps where the account is still working. That is the only way in right now.
2. Check for any other sign-in methods
   On the laptop, go to the security/MFA settings for the account (for work/school this is usually the Security info or Additional security verification page).
   Look for:
   • Phone (SMS or call)
   • Email code
   • Security key If any of these exist, use them to sign in on the new phone instead of Authenticator.
3. If there is another MFA method, add the new phone
   Still on the laptop (already signed in):
   • Open the Security info / Additional security verification page.
   • Add a new sign-in method (phone or Microsoft Authenticator on the new device).
   • Complete the prompts. Once added, use that method to sign in on the new phone.
4. If Authenticator says “Authentication did not complete”
   On the new phone:
   • Make sure the Microsoft Authenticator app is unlocked (open it and unlock the phone/app).
   • Turn notifications ON for Authenticator in phone settings.
   • Make sure the phone has internet (try switching between Wi‑Fi and mobile data).
   • Check the phone’s date and time are set correctly.
   • Make sure the app is updated to the latest version from the app store.
5. If this is a work or school account and Authenticator is the only method
   • Contact the organization’s IT help desk / Microsoft 365 admin and ask them to reset MFA for the account.
   • They can go to the Entra/Microsoft 365 admin portal and choose Require re‑register multifactor authentication for the user.
   • After they reset it, sign in again on the laptop or new phone and set up Authenticator from scratch.
6. If this is a business tenant and there is only one admin (you)
   • A Microsoft Data Protection engineer is needed to reset the admin’s MFA.
   • Use the official Customer service phone numbers - Microsoft Support line, follow the phone prompts, and clearly state:
     • Using Office 365 for business
     • It is a company account
     • You are the only administrator and are locked out by Authenticator
   • Ask them to open a service request and escalate to the Data Protection team to reset MFA for the admin account.
7. If this is a personal Microsoft account and you forgot the password
   • Use the official Reset your password flow: Reset your password.
   • After getting back in, go to the security info page and add the new phone/Authenticator as a method.
8. If nothing else works and you still have laptop access
   • For work/school: contact the organization’s admin or Microsoft support as above to have MFA cleared.
   • For personal: use the password reset link and recovery options (email/phone) to regain full control, then re‑set MFA.

Do not remove or change anything on the laptop account until a new MFA method is added and tested on the new phone.

References:

• Authentication did not complete
• Troubleshoot problems with Microsoft Authenticator
• Use a screen reader to set up and troubleshoot multifactor authentication
• How Do I Regain Access to My Account After Losing Access to Microsoft Authenticator? (Urgent Request). - Microsoft Q&A
• Cannot authenticate with E-mail when logging into Microsoft Authenticator(iOS). - Microsoft Q&A
• I have a Micrsoft business account and I am the admin and the only user registered under this account. I can't log in because i have replaced my phone and the authenticator doesn't work. - Microsoft Q&A
• Microsoft authenticator sending me into a spiral - Microsoft Q&A
• Requesting a Tenant Admin MFA Reset - Microsoft Q&A
• Common problems with two-step verification for a work or school account
• Authenticator Did Not Complete Login