Password Prompt Loop After Enabling Office 365 MFA

Scenario: you enable multi-factor authentication (MFA) for a user in Office 365, they go through and configure it but then they keep getting prompted for credentials in Outlook and can’t proceed.

Additional Symptom:

The prompt box is the old school type and not the modern authentication style.


Modern auth may be disabled on the tenant.

Run this PowerShell against the tenant:

Get-OrganizationConfig | Format-Table Name,OAuth* -Auto

If it gives false, modern auth needs enabled and this is your issue.

Run this to enable it. Takes affect nearly immediately and no negative impact:

Set-OrganizationConfig -OAuth2ClientProfileEnabled $true

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