I tested again the installation and the configuration of the “Account provider: Samba Active Directory” (I have at home a computer for tests), without to reboot the server between the installation of the package and the configuration of the Samba AD.
I had the same error at the end of the configuration process but I observed that the “START DC” button was still active.
Without leaving the page, I have enabled the “Create a bridge interface for the green network” and then I pressed the “START DC” button. After that, the process of the Samba AD ended without issues.
After that, I have created a new user, with password setting during the process, without issues.
The link for the “message” log for this:
Timeline in the “message” log:
19:20:02 - 19:20:19 -> Install the Samba AD package
19:21:25 - 19:24:25 -> First attempt of the Samba AD configuration
19:25:24 - 19:25:51 -> Second attempt of the Samba AD configuration
19:27:21 - 19:27:14 -> Changing the Admin password of the Samba AD