Hi,
Usually the reset from the console or portal should fix the issue however can you please follow the steps below to reset and unblock MFA in Azure Active Directory via Azure Portal and PowerShell.
Using Azure Portal:
Sign in to the Azure portal with the tenant Global Administrator account.
Navigate to Azure Active Directory > Users > All users > Choose the user you wish to perform an action on > select Authentication methods > Require Re-register MFA.
Once this is done, the next time the user signs in, he/she will be requested to set up a new MFA authentication method.
Note: The user's currently registered authentication methods aren't deleted when an admin requires re-registration for MFA. After a user re-registers for MFA, we recommend they review their security info and delete any previously registered authentication methods that are no longer usable.
Using PowerShell:
Install the MSOnline PowerShell module.
Run Connect-MSOLService and sign in with the Global Administrator account.
Run Set-MsolUser -UserPrincipalName John.dave@Company portal .com -StrongAuthenticationMethods @() cmdlet to reset the MFA registration information.
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