Password incorrect after AD Connect sync

Question

We have configured Azure AD Connect with Password Hash Synchronozation for SSO. To check if everything is working, we created a test user on-premise AD

User: Luke Shaw
Username: LShaw@keyman .com
Password: !Jack.1786@
Email: Luke.Shaw@ae.rlb.com

We ran the sync which was a success. Now we see the users Under Active Users in M365 Admin Portal. We assign the license to this user. However when I try to login to mail.office365.com with the

Username: LShaw@keyman .com
Password: !Jack.1786@

says password incorrect.

I am able to login to a corporate AD joined computer using

Username: DOMAIN\LShaw
Password: !Jack.1786@

Now when I open Outlook for the 1st time, it automatically discovers the SMTP but when I hit "Connect" it prompts for password and on entering the password it throws the password window again meaning the password is incorrect

I am trying to figure out what maybe wrong or missing here.

Answer 1

How long did you wait to test after enabling the feature? Its not always immediate.

Are you able to check the sign in logs for the error?

https://learn.microsoft.com/en-us/azure/active-directory/hybrid/tshoot-connect-sso#sign-in-failure-reasons-in-the-azure-active-directory-admin-center-needs-a-premium-license