review the password policy and status
samba-tool domain passwordsettings show
eventually tune the policy
samba-tool domain passwordsettings -h
create a new user really quick
pwgen samba-tool user add user1
–or– with more details
samba-tool user add user2 \ --given-name=user2-firstname \ --surname=user2-surname \ --mail-address=USER2@DOMAIN.TLD \ --login-shell=/bin/bash
and check
samba-tool user list
https://www.tecmint.com/manage-samba4-active-directory-linux-command-line/A
https://wiki.samba.org/index.php/Adding_users_with_samba_tool