Login attempt failed even though password correct
I am able to log into an AzureAD joined machine, by configuring the following settings in the RDP item:
General | Host: fill in the actual computername, not the IP Address.
General | Username: your UPN (email address)
General | Password: your relevant password
General | Authentication: leave the Enable Network Level Authentication (NLA) option enabled. Enable it, if it is not.
General | Authentication: enable the Enable Azure AD SSO option. This one will allow you to remote in on the machine.
Leave everything else as default
Additionally, if you have Intune/Autopilot, you might want to create an Configuration Profile where you configure the OMA-URI for adding additional admin accounts to the Local Admin group. The above settings will allow you to log on with other authorized user accounts (e.g. IT engineers).