\Gtk-Message: (time): Failed to load module “canberra-gtk-module”

I am running Ubuntu 18.04.2 LTS. I am wireless networked to a HP OfficeJet 5200 printer which was working fine a week ago.
Now it does not work and when I select print in Libre office I only see the "generic printer".
I tried to load the latest version of HPLIP driver - version 3.19.10
In terminal mode I typed • sudo add-apt-repository ppa:hplip-isv/ppa
    • I typed the required password, then typed: sudo apt-get update, then: sudo apt-get install hplip

When I try to print I get "generic printer" but cannot see nor print from my HP OfficeJet 5200.

In my /Downloads folder I have a hplip-3.19.10 folder which is now full of a lot of sub folders & files, but I have no idea whether they are the correct ones, and a search for canberra-gtk-module (the file teminal failed to load) in the hplip-3.19.10 folder produces "No results found".

Please help. Thank you!