Register Microsoft Authenticator on a New Phone
If you have recently upgraded your phone or lost access to your Microsoft Authenticator app, you may find yourself in a "login loop" where the system asks for a code from the very app you cannot access.
Follow these steps to break the loop and register your new device.
Method 1: If You are Still Logged In on a Computer (Fastest)
If you have a laptop or desktop where you are already signed into your email or Microsoft account, you can update your security settings without needing a new code.
Open Security Info: Go to the Microsoft Security info page
Verify Your Identity: If prompted to sign in and it asks for an Authenticator code, click "I can't use my Microsoft Authenticator app right now" or "Sign in another way." Note: Most accounts have a backup method like a text message (SMS) or a secondary email. Choose one of those to finish the login.
Add Your New Phone: Click + Add sign-in method.
Choose Authenticator app from the dropdown.
Follow the on-screen prompts to install the app on your new phone and scan the provided QR code.
Remove the Old Phone: Once the new phone is successfully added, find your old device in the list and click Delete. This prevents confusion during future logins.
Method 2: If You are Completely Locked Out
If you cannot log in on any device and do not have a backup SMS or email option configured, you will need administrative assistance.
Contact the Helpdesk: Submit a Helpdesk ticket and Technology staff will assist you.
What to ask for: Request that they "Require re-register multifactor authentication" for your account.
What happens next: The admin will clear your old settings. The next time you log in to Microsoft 365 on any device, you will be automatically prompted to set up the Authenticator app as if it were your first time.
Proactive Tips
Add a Secondary Method: Always ensure you have at least two ways to verify your identity (e.g., the Authenticator app plus a mobile phone number for SMS).
Important: Never delete the Authenticator app from your old phone until you have confirmed the new phone is working perfectly!