Better error message for "forbidden".

[rewolff]

I installed a fresh machine. During install it asked me for my "normal user" account. In my experience this adds the new user to system groups like "sudo" and other system groups. The sudo worked.

But it took me a while to figure out the cups "Forbidden" message. Turns out I had not been added to "system" and "lp" groups. IMHO the message should be something like: "login succesful, your user does not have the required permission for this action. "
That would've helped me a lot.

[michaelrsweet]

Will consider our options here; RFE for Future.

[michaelrsweet]

[master e923f65] Explain the "forbidden" error better (Issue #5547)