Comment 9 for bug 1573221

@mmaurice Have you checked that winbindd is actually running?

IIRC between 4.1 and 4.2 the parameter for winbindd in the 'server services =' line in /etc/samba/smb.conf changed from 'winbind' to 'winbindd'. This will have been picked up automatically if the line only had "+" and "-" entries, or was absent altogether. However if you explicitly specified the services, then if 'winbind' was there, you'll need to change it to 'winbindd'.