Exchange Migration: Windows 10’s Outlook kept prompting after turn off modern authentication

If you had read my previous/recent post about exchange migration on Windows 7, then today I’m writing a post about Windows 10. https://sabrinaksy.com/2021/10/14/exchange-migration-outlook-kept-prompting-for-password-after-migration/

It seems that after we turn off the modern authentication, there was no more further prompt issues with Windows 7 but Windows 10 on the next day is receiving prompt and with the user name shows as “contoso.onmicrosoft.com” domain instead of the “contoso.com” registered domain or default domain.

After research, we notice Microsoft just recently release an enforcement towards basic authentication on 1st October 2021. Hence, we have no choice to look for workarounds for Windows (7 and 10) to support Modern Authentication. The only workaround is to create a registry and amend them to the Windows machines.

Workaround

  1. Create a Group Policy Object in your Active Directory environment
  2. Under the Computer > Preferences > Windows Settings > Registry
  3. Create a new registry item
  4. This is the registry item that we want to create
    • Path: HKEY_CURRENT_USER\Software\Microsoft\Exchange
    • Value Name: AlwaysUseMSOAuthForAutoDiscover
    • Value: 1
    • Type: REG_DWORD
  5. Once you have created this policy and link it to the particular organization unit that contains the Windows machines
  6. Run a force group policy update from the Active Directory server
  7. Go back to the Office 365 admin center portal with Global administrator rights
  8. Settings > Org Settings > Modern Authentication > Turn on modern authentication
  9. Make sure you select all of the items under the modern authentication

  1. Monitor for the next 24 to 48 hours, for further prompt issues
  2. If there’s issues, troubleshoot the machine and check is registry amended if not just manually run it

You can always export the registry settings as .reg file format, so is easier to install on the affected machine(s) just by double clicking the .reg file.

How to export the registry file?

You can use the PowerShell’s Invoke-Command

Invoke-Command {reg export 'HKEY_CURRENT_USER\Software\Microsoft\Exchange' C:\Temp\ModernAuth.reg}

References:

  1. https://techcommunity.microsoft.com/t5/exchange-team-blog/basic-authentication-and-exchange-online-september-2021-update/ba-p/2772210
  2. https://docs.microsoft.com/en-us/outlook/troubleshoot/authentication/outlook-prompt-password-modern-authentication-enabled

Author: sabrinaksy

Just an ordinary lady who love what she does best.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

%d bloggers like this: