Microsoft Authenticator and Teams log in issue

It sounds like the MFA registration is still tied to the old phone, so you’re stuck in a sign-in loop. Since this is a work account, I would contact your company’s Microsoft 365/Entra admin or IT team and ask them to reset your MFA registration.

They can go to Microsoft Entra admin center > Users > your account > Authentication methods > Require re-register multifactor authentication. After that, your next sign-in should let you set up Microsoft Authenticator again on the new phone. Microsoft documents this as the supported way to re-register MFA when the existing Authenticator method is no longer available.

If you still have another verification method available, such as SMS or a phone call, try that first. Otherwise, the admin reset is likely the quickest way to break the loop.

Hi Alliah,

I hope you're doing well.

Sorry to hear you're having trouble signing in to your Microsoft account.

From what you've described, it sounds like your Multi-Factor Authentication (MFA) setup may need to be reset. This can sometimes happen after switching to a new device, replacing a phone, or reinstalling the Microsoft Authenticator app. Since your new device hasn't been registered yet, the authentication requests may still be linked to your previous device, which can leave you stuck in a sign-in loop.

Because you're using a work or school account, the MFA settings are managed by your organization's IT administrator. Unfortunately, this isn't something that can be reset from the user side.

I'd recommend reaching out to your organization's IT administrator and explaining that you're unable to sign in because you're stuck between Microsoft Teams and the Microsoft Authenticator app and are no longer receiving authentication prompts or codes.

You can specifically ask whether they can:

• Reset your MFA settings
• Require MFA re-registration
• Remove your existing Authenticator registration so you can set it up again

You may also want to share the following Microsoft article with them: Manage authentication methods for Microsoft Entra multifactor authentication - Microsoft Entra ID | …

If you are unsure who your IT administrator is, you can refer to this official Microsoft guide for assistance: How do I find my Microsoft 365 admin? - Microsoft Support   

Once your IT administrator resets your MFA registration, you should be able to sign in again and go through the Microsoft Authenticator setup process from the beginning, including scanning a new QR code on your device.

I hope this points you in the right direction. If you receive any updates from your IT team or run into any issues along the way, feel free to reply back with more details and I'll be happy to help further.

Best regards,