> Does a screen notification about firmware or a plug-in show up?
Yes.
> Does a utility show up to download a plug-in for HPLIP?
No. Also if user trying to install hplip-gui and use hp-setup for download and install plugin they (hp-setup utility) can't download plugin too with error "No internet connection" (actually internet connection is fine).
> Can you run the following commands in a terminal window and post the output here
> Can you also attach the PPD files in /etc/cups/ppd/?
I try to do this tomorrow or the day after, when I have access to this printer.
> Does a screen notification about firmware or a plug-in show up?
Yes.
> Does a utility show up to download a plug-in for HPLIP?
No. Also if user trying to install hplip-gui and use hp-setup for download and install plugin they (hp-setup utility) can't download plugin too with error "No internet connection" (actually internet connection is fine).
> Can you run the following commands in a terminal window and post the output here
> Can you also attach the PPD files in /etc/cups/ppd/?
I try to do this tomorrow or the day after, when I have access to this printer.