Ubuntu – System printing service not available ubuntu 18.10

I have a problem with the system printing service:

My usb printer used to work just fine, and then I tried to a setup print-server – the whole system hanged up, and after reboot, no matter what I do, I have this message from the GUI settings for printers …

System printing service not available:

I was trying to restart cups.service and cups.socket as advised in :

Ubuntu 18.04 LTS — Printing Service Not Available
Printing service not available

and cups.socket stays "green" until I look up into the GUI settings for printers, which seems to do something that resets cups.socket again …

Here is a screenshot of the "best" cups situation:

and that's how it looks like right after I check out the GUI printing settings:

I also tried to reinstall cups, – no luck here either.

Any help/advice is appreciated, as I really don't want to reinstall the system, and chances are everything would crash again after I attempt to setup the print-server …