Comment 2 for bug 1688527

The "samba" systemd service should not be enabled:

พ.ค. 05 17:30:17 hostname samba[11118]: [2017/05/05 17:30:17.311253, 0] ../source4/smbd/server.c:372(binary_smbd_main)
พ.ค. 05 17:30:17 hostname samba[11118]: samba version 4.3.11-Ubuntu started.
พ.ค. 05 17:30:17 hostname samba[11118]: Copyright Andrew Tridgell and the Samba Team 1992-2015
พ.ค. 05 17:30:17 hostname samba[11119]: [2017/05/05 17:30:17.355042, 0] ../source4/smbd/server.c:477(binary_smbd_main)
พ.ค. 05 17:30:17 hostname samba[11119]: At this time the 'samba' binary should only be used for either:
พ.ค. 05 17:30:17 hostname samba[11119]: 'server role = active directory domain controller' or to access the ntvfs file server with 'server services = +smb' or the rpc proxy with 'dcerpc endpoint servers = remote'
พ.ค. 05 17:30:17 hostname samba[11119]: You should start smbd/nmbd/winbindd instead for domain member and standalone file server tasks
พ.ค. 05 17:30:17 hostname samba[11119]: [2017/05/05 17:30:17.355198, 0] ../lib/util/become_daemon.c:111(exit_daemon)
พ.ค. 05 17:30:17 hostname samba[11119]: STATUS=daemon failed to start: Samba detected misconfigured 'server role' and exited. Check logs for details, error code 22
พ.ค. 05 17:30:27 hostname samba[11122]: [2017/05/05 17:30:27.442565, 0] ../source4/smbd/server.c:372(binary_smbd_main)
พ.ค. 05 17:30:27 hostname samba[11122]: samba version 4.3.11-Ubuntu started.
พ.ค. 05 17:30:27 hostname samba[11122]: Copyright Andrew Tridgell and the Samba Team 1992-2015
พ.ค. 05 17:30:27 hostname samba[11123]: [2017/05/05 17:30:27.488643, 0] ../source4/smbd/server.c:477(binary_smbd_main)
พ.ค. 05 17:30:27 hostname samba[11123]: At this time the 'samba' binary should only be used for either:
พ.ค. 05 17:30:27 hostname samba[11123]: 'server role = active directory domain controller' or to access the ntvfs file server with 'server services = +smb' or the rpc proxy with 'dcerpc endpoint servers = remote'
พ.ค. 05 17:30:27 hostname samba[11123]: You should start smbd/nmbd/winbindd instead for domain member and standalone file server tasks
พ.ค. 05 17:30:27 hostname samba[11123]: [2017/05/05 17:30:27.488815, 0] ../lib/util/become_daemon.c:111(exit_daemon)
พ.ค. 05 17:30:27 hostname samba[11123]: STATUS=daemon failed to start: Samba detected misconfigured 'server role' and exited. Check logs for details, error code 22

The samba service should be masked, like this:
# systemctl status samba
● samba.service
   Loaded: masked (/dev/null; bad)
   Active: inactive (dead)

If yours says otherwise, please mask it:
# systemctl mask samba
Created symlink /etc/systemd/system/samba.service → /dev/null.