Lost printer connection maybe associated with network name issue.
 

Linuxmint Mate Uma 20.1

I lost connection to my network printer.
Went to Network and found it called 'Windows Network' with properties of 0 bytes and unknown, unknown, unknown.
I am still connected to internet via the network modem which I believe should be the network name.
I upgraded the system to Mate 21.1 (Vanessa or Vera). Didn't help.
So, I imagine that the 'Windows Network' is invalid (don't know if,when or why it changed) and that is why the printer isn't connecting. It works via USB.
So I am imagining that if I change the network name to the real one that all will be good. But I don't know and I don't know how.
Any clues?
Graeme
More information- in properties of network-(application/octet-stream)

I need one things cleared up.
Why do you call it your "network printer" if it is directly connected using USB?

If this is a wireless printer then simply add a fixed IP in the appropriate subnet to the printer as the first step.
For example, if your network is 192.168.1.0/24 you could choose to assign 192.168.1.200 to the printer.
Then on the host configure the printer as a network printer at whatever address you assigned to that printer using the cups interface. If you assigned it as 192.168.1.200 and your host is 192.168.1.2 then the cups interface would be at http://127.0.0.1:631 and you should be able to configure that printer.

Thank you both.
It has always been a network printer but I plugged it in via USB to test it and to try and connect it that way.
Couldn't. The printer is invisible to the network though it was connected just fine before.
On every other computer here the network name is the name of the modem. I don't know where the Windows Network name came from but I suspect it is bogus and the computer is looking there for the printer.
Funny thing is I am connected to the modem just fine.
I am a bit naive re programming. Is the subnet one of the boxes that comes up when I try to connect? There is a blank box for location there. Is the host my IP number. How do I get the network number?
thanks again,
Graeme

IP networks need IP network addresses, masks, sometimes ranges: they do not use names in general. NODE names are resolved by name services (Generally the host table or DNS/BIND services. If you have a DHCP server (WIFI routers generally do this) then it will act as your DNS service locally. Network names are a Microsoft/Windows networking thing ported over form the old ETH-II days and retained ever since. If you are not running Microsoft/Windows instances it can probably be ignored.

If your printer is USB attached then the node it is attached to uses it as a device, not a network target. If it is not working directly attached, something may be wrong with the printer blocking it form working AT ALL! I would troubleshoot it there, at the printer, before I look at networking from external devices.

Can that printer output a status page or settings page? That is generally done form the menu on the printer itself and may prove illuminating.
If it has that option, but cannot perform that option, then you DO have a problem at the printer and can address that issue.

I put 120.1.0.0.631 into the location box and it printed a test page via the network. Happy days!
So the remaining question of interest is the network icon giving no information on the network and how to investigate that.
Graeme

What network icon are you referring to?

In the file browser in Networks is 'Windows Network' which has all unknown properties except for in type it says unknown and then 'application/octet-stream'
Trying to open it results in an error message- Unable to mount location. Failed to retrieve share list from server:No such file or directory.

If you have no windows network or domain servers that is to be expected. You need to look at the IP network, not Windows, for CUPS printers. Or, just use the CUPS software which is optimized to LOOK for printers. Your menus should have printer settings options that leverage CUPS.

Before you investigate printer connections, I would verify that the printer actually WORKS!

The file browser's "windows network" is unrelated to any printer problems you were or might be having. It is or was a way to automatically find Windows computers and their shares on the network including linux PC's running samba. It originally uses/used SMB version 1 netbios for browsing but since SMB V1 is now deprecated and disabled in Windows 10 and the more recent versions of samba so it has become a bit harder to browse for shares which is one reason you are probably seeing the error message. If it used to work then an upgrade that included a newer version of samba might have caused it to now be broken.

cups which is the linux printing service handles browsing for printers. Is the printer a standalone network device or always connected to a computer? Do you have other Windows computers on your network?

Solution didn't last
 

The printer is unreachable again!
I entered system-config-printer in terminal and generated the below text. Greek to me!
Can anybody translate into fixit action?

graeme@graeme-Satellite-L850:~$ system-config-printer
/usr/share/system-config-printer/system-config-printer.py:325: DeprecationWarning: Gtk.ActionGroup.list_actions is deprecated
for action in printer_manager_action_group.list_actions ():
/usr/share/system-config-printer/system-config-printer.py:326: DeprecationWarning: Gtk.Action.set_sensitive is deprecated
action.set_sensitive (False)
/usr/share/system-config-printer/system-config-printer.py:334: DeprecationWarning: Gtk.ActionGroup.get_action is deprecated
act = printer_manager_action_group.get_action (action)
/usr/share/system-config-printer/system-config-printer.py:364: DeprecationWarning: Gtk.UIManager.ensure_update is deprecated
self.ui_manager.ensure_update ()
/usr/share/system-config-printer/system-config-printer.py:365: DeprecationWarning: Gtk.UIManager.get_accel_group is deprecated
self.PrintersWindow.add_accel_group (self.ui_manager.get_accel_group ())
/usr/share/system-config-printer/system-config-printer.py:374: DeprecationWarning: Gtk.UIManager.get_action is deprecated
action = self.ui_manager.get_action ("/new-printer")
/usr/share/system-config-printer/system-config-printer.py:375: DeprecationWarning: Gtk.Action.create_menu_item is deprecated
newprinteritem = action.create_menu_item ()
/usr/share/system-config-printer/system-config-printer.py:673: DeprecationWarning: Gtk.Action.get_proxies is deprecated
for widget in action.get_proxies ():
/usr/share/system-config-printer/system-config-printer.py:986: DeprecationWarning: urllib.parse.splittype() is deprecated as of 3.8, use urllib.parse.urlparse() instead
(scheme, rest) = urllib.parse.splittype (object.device_uri)
/usr/share/system-config-printer/system-config-printer.py:2246: DeprecationWarning: Gdk.threads_enter is deprecated
Gdk.threads_enter ()
/usr/share/system-config-printer/system-config-printer.py:2197: DeprecationWarning: Gdk.threads_leave is deprecated
Gdk.threads_leave ()

Thank you,
Graeme

It looks like either PYTHON has been messed up, or system-config-printer has.
I would do a clean install of system-config-printer if possible.

Did you install something manually, bypassing the package management?

Thank you,
Can you show me the command for 'clean install of system-config-printer' if possible.
Graeme

$ sudo apt install system-config-printer
[sudo] password for graeme:
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
system-config-printer is already the newest version (1.5.16-0ubuntu3).
0 to upgrade, 0 to newly install, 0 to remove and 1 not to upgrade.

This was the result of the install command.

Use the force option.
Or you could remove with purge, then install and reconfigure clean.
Based upon those errors, this may obsolete some python libs. If you remove and get prompted to autoremove some packages: do. Record what you remove. When you install the new system-config-printer from the repo it should pull in any of the removed packages that it needs.