Hi @MV
Thank you for reaching us!
I understand that users from domain B password is not working and when you change the password the user is not able to login and getting error message credential wrong. but when user use the previous password d it works fine.
Could you please verify that the authentication agent is installed and configured properly on your on-premises. If users are unable to sign in with a new password after configuring PTA, it is possible that the PTA agent is not working correctly or is not able to communicate with the on-premises Active Directory. In this case, you can check the status of the PTA agent and ensure that it is installed and configured correctly.
If the issue is not with the PTA agent, it might be the issue with the incorrect user's on-premises UserPrincipalName (UPN) is different than the user's cloud UPN. In instance, the username may not be the same as email address and the UPN for the user may have a different suffix than the custom domain.
For more information, please go through Users get invalid username/password error.
Also, please refer this thread which is similar to this issue. and refer Troubleshoot Microsoft Entra pass-through authentication
Hope this helps. Do let us know if you any further queries by responding in the comments section.
Thanks,
Akhilesh.
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