Microsoft Authenticator App

Question

I’ve bought a new iPhone - factory reset my old phone.

The authenticator app on my new phone says I need to sign in to the email accounts again in order for me to use the app. However, when I put my password to these accounts in (in order to sign in) it asks me to verify them using the app….. but all of this is happening within the app itself.

I’ve also tried signing in to the email accounts via other devices etc and it continuously asks to verify using the app but the app isn’t working because my accounts within the app aren’t signed in!

I’m completely stuck because without it I cannot access any emails/meetings from home (I work in the [Moderator note: personal info removed] ).

Please help!

Answer 1

Hello @Siobhan Hooper,

Welcome to the Microsoft Q&A Forum and thank you for your question. 

Based on the information you shared, it appears that your account is part of an organization. When an account belongs to a company or institution, the Multi‑Factor Authentication (MFA) settings are fully managed by the organization's IT administrators, and only they have the ability to reset or revoke those authentication methods. 

If you are an end user within your organization, the best next step is to contact your internal IT support team. They can quickly help you regain access by resetting your MFA configuration on their side. This process is straightforward for them, and they can perform it using the Microsoft Entra admin portal. They can revoke and require re-registration of Multi-Factor Authentication (MFA) settings for your account by following these steps:  

• Sign in to the Microsoft Entra Admin Center  
• Navigate to Users > Your Account > Authentication methods  
• Select Require re-register MFA 

 After this is done, you will be able to sign in and set up the Authenticator app again.

You may share this official Microsoft article with them for detailed guidance: Manage authentication methods for Microsoft Entra multifactor authentication - Microsoft Entra ID |…     

If you are the IT administrator of the Microsoft tenant, please let me know, I will be happy to provide additional steps or guidance specific to admin‑level access. 

Feel free to reach out anytime if you need further clarification. I'm here to help. 

Kind regards, 

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Answer 2

The accounts must be re-registered for multifactor authentication (MFA) on the new iPhone. Because the old phone was factory reset and Authenticator wasn’t backed up/restored first, the app on the new device no longer has valid MFA credentials, which causes the “endless loop” when trying to sign in.

Use one of these supported paths, depending on the type of account and what access still exists:

1. If there is another MFA method configured (SMS/call/email)

• When prompted to approve in Authenticator, choose the “I can’t use my Microsoft Authenticator app” or “Use a different verification option” link.
• Select SMS or phone call if available.
• After signing in successfully, go to the account’s security/MFA settings and:
  • Remove the old Authenticator registration.
  • Add the new phone by setting up Microsoft Authenticator again.

2. If this is a work/school (NHS) account and there is an IT admin

• Contact the organization’s IT/service desk and ask them to reset MFA for the account.
• In Microsoft Entra, an admin can:
  • Go to Users → [account] → Authentication methods.
  • Use Require re-register multifactor authentication to force a fresh setup.
• After the reset, sign in again and register the new Authenticator app using the QR code provided.

3. If this is a personal Microsoft account and no other MFA method works

• Use any still-signed-in session (for example, on a Windows PC or browser) to access the account’s security settings and add an alternate sign-in method (SMS/phone/email) before trying to sign in on the new phone.
• If no signed-in session exists and no alternate method works, recovery must be done through Microsoft’s automated account recovery and security processes; manual bypass is not available in the provided context.

4. For future device changes

• Before switching phones, do not factory reset or remove Authenticator from the old device until the new device is fully set up and working.
• For iOS, enable backup for Authenticator so accounts can be restored on a new iPhone as described in the backup guidance.

If none of the above options are available and this is an NHS work account, escalation through the organization’s IT/security team is required so they can work with Microsoft support to regain access.

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References:

• Use a screen reader to set up and troubleshoot multifactor authentication
• Troubleshoot problems with Microsoft Authenticator
• Migrate to a new iPhone for work
• Back up your accounts in Microsoft Authenticator
• Microsoft Authenticator FAQs
• Microsoft authenticator sending me into a spiral - 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