[Samba] Upgraded from CentOS 6.X to 7.X, samba not working

[Jobst Schmalenbach]

Hi

Previous: CentOS 6.X, samba4.x86_64 4.2.10-15.el6
Now: CentOS 7.6.1810, samba 4.8.3-4.el7

When I start smb, nmb or winbind I get no errors at all.
This is all I get:

  May 24 22:44:04 HOST systemd[1]: Starting Samba SMB Daemon...
  May 24 22:44:05 HOST systemd[1]: smb.service: main process exited, code=exited, status=1/FAILURE
  May 24 22:44:05 HOST systemd[1]: Failed to start Samba SMB Daemon.
  May 24 22:44:05 HOST systemd[1]: Unit smb.service entered failed state.
  May 24 22:44:05 HOST systemd[1]: smb.service failed.

Looking at the samba logs, they are all empty.
The journal has not much info either.

What the hell am I doing wrong?
Are there massive changes between 4.2 and 4.8 that its not working?

Help please, I have till Monday morning to get this sorted (weekend).

jobst