To reset multi-factor authentication for a user:

1. Log in as administrator.
2. Navigate to More 
3. Select User admin.
4. Select the three dots next to the user for whom you want to reset the authentication. 
5. Click "Reset MFA" (Multi-Factor Authentication).

Wait until the task is completed and you receive a confirmation of the MFA reset.
Instruct the user to log in in a few minutes and follow the prompts to enter their mobile number or register their Microsoft Authenticator account.

Note! This process is necessary when users update their mobile number or reinstall the authenticator app.