Re-register MFA for a user

If you have a user that is having issues logging in with MFA, Require Re-register MFA will make it so that when the user signs in next time, they will be requested to setup a new MFA authentication method.

To re-register MFA for a user in Azure, you can follow these steps:

1. Sign in to the Azure portal.
2. On the left-hand side, select "Azure Active Directory" and then click on "Users" and "All Users".
3. Choose the user you want to re-register MFA for and select "Authentication Methods".
4. Click on "Require re-register MFA" and save the changes.

By performing these steps, the user will be prompted to set up a new MFA authentication method the next time they sign in. 

Microsoft link: Manage user authentication methods for Microsoft Entra multifactor authentication