Groupoffice stuck after LDAP AD sync

[Gnggi]

Hi, I'm new with groupoffice and want to test it if we can use it for our small company at Ubuntu 24.04 Server .
I have installed groupoffice and groupoffice-mailserver according the manual. Then installed letsencrypt and there are no problems with SSL login and all other.
Then installed LDAP module to connect to AD. After LDAP sync of users and groups no more login was possible, not as system user (not in AD) nor as any AD-user. Error message is "Bad username or password"
Nevertheless I can login at console as system user.
Did it all on a fresh installed Ubuntu server (Debian packages) multiple times with same result.
Any hints are welcome.

[Gnggi]

Found the solution after next try: The name of the system user should not exist in AD otherwise the login fails after AD sync.