Comment 4 for bug 1719889

net groupmap list only shows Administrators and Users.

the problem does not exist on 18.04.

I realize it's not a bug "in ubuntu", but in the version of samba that ubuntu 16.04 is using. from experience I can tell you that reporting it to samba is just going to result in them saying "compile your own newer samba version", which does nothing to get ubunut's LTS samba package to not give this message.