Debian and debian-derivatives changed the service name from 'samba' to 'smbd'.

[pve]

NAS/SMB setup gives;
Failed to start samba.service: Unit samba.service is masked.

See http://askubuntu.com/questions/754572/cannot-restart-samba-samba-service-is-masked

This solved my problem.

[ramontayag]

Thanks @pve. I couldn't get to that link, but this might be referring to the same issue.