Unable to login into authenticator app

Use Sign in another way if it is offered; if no alternative verification method is available, ask your organization’s IT administrator to reset your MFA registration so you can enroll Microsoft Authenticator on the new phone.

1. Check for another sign-in method

1. Return to the Teams or Microsoft 365 sign-in page.
2. Select Sign in another way or I can’t use my Microsoft Authenticator app right now.
3. If offered, verify with a previously registered method such as an SMS, phone call, security key, or passkey.
4. After signing in, open Security info, select Add sign-in method → Microsoft Authenticator, and follow the QR-code setup.

Restoring Authenticator from backup is not enough for an organizational account: only the work or school account name is restored, and the account must be signed in and configured again on the replacement phone.^1^

2. If no alternative method is available

Contact the IT help desk for the organization that provided your Teams account. Use this request:

My old phone is unavailable, and Microsoft Authenticator on my new phone says, “Sorry, we’re having trouble verifying your account.” Please require me to re-register MFA or reset my authentication methods.

This change must be performed by an authorized tenant administrator; installing Authenticator again or resetting the Teams password will not by itself register the new device. Similar work or school account cases require the organization’s IT team to reset MFA before enrollment can start again.^2^

The administrator can perform the reset as follows:

1. Sign in to the Microsoft Entra admin center as at least an Authentication Administrator.
2. Go to Entra ID → Users.
3. Select your user account.
4. Select Authentication methods.
5. Select Require re-register MFA.

This removes registered Authenticator methods and prompts you to configure a new MFA method at the next sign-in.^3^

3. Register the new phone after the reset

1. Sign in to Teams or Microsoft 365 with your work or school account.
2. When prompted for additional security information, choose Microsoft Authenticator.
3. On the new phone, open Authenticator and tap +.
4. Select Work or school account → Scan QR code.
5. Scan the QR code displayed on the computer.
6. Approve the test notification or enter the displayed number.
7. Confirm that the setup finishes successfully, then test a new Teams sign-in.

If this is the organization’s only administrator account, normal administrator-assisted reset is unavailable; Microsoft Support must verify tenant ownership and assist with account recovery.^4^

References

1. Transfer Microsoft Authenticator account entries to a new phone
2. authenticator app issue after changing to a new phone - Microsoft Q&A
3. Manage user authentication methods for Microsoft Entra multifactor authentication
4. Unable to log into Authenticator app - Microsoft Q&A