How to Enable Modern Authentication in Office 365 if you have MFA (Multi-Factor Authentication)

Enabling Modern Authentication in your Office 365 tenant may be the solution if you have Office 365 MFA enabled and Outlook constantly prompts for a password for your Office 365 account.

MFA offers an additional security verification process but it is not without its glitches.  Outlook is one of the most common applications that suffers from constantly changing MFA strategies with app passwords being a common work around for the MFA requirement. 

Recently, MessageOps encountered a situation within our client’s Office 365 environment where Outlook on a Windows 10 machine stopped accepting app passwords as well as the client’s actual password. We followed the following steps to enable Modern Authentication thus granting the client reentry.

The client’s environment

  • Office 365 E3 subscription
  • Latest Office applications installed on Windows 10 (1903)
  • Office MFA enabled and configured (enforced) for my account
  • Admin rights to my O365 tenant


  1. Remove any Outlook saved credentials using the Windows Credential Manager

    • Click start and type in “credential” and open Credential Manager.
    • Select Windows Credentials
  2. Remove any credentials associated with Office and your O365 account

    • Look for anything starting with “MicrosoftOffice16”…
    • Ensure you do not remove credentials for accounts other than the problematic account.
  3. Go to your security profile and delete any previously created app passwords for Outlook

  4. ** Ensure Modern Authentication is enabled for your Office 365 tenant.

    • Sign into your Office 365 Admin Center using your O365 account with admin permissions.
    • Using the navigation menu select Settings > Services & add-ins
    • Then select ‎Modern authentication‎ and enable the option

  5. When Outlook is next opened the password prompt should be for the Office 365 account in question.

    • Enter the actual password and follow any subsequent prompts.
    • If multiple accounts are in Outlook, ensure the problematic account is being accessed to cause the password prompt.
  6. If password prompts persist, try removing then re-adding the O365 account.


Windows 10 PCs as well as Android phones have all had issues successfully resolved once the Modern authentication option was enabled.  Please use caution when working with older email clients as enablement may be problematic.

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