Scanning to network folder

I have Mate 18.04 installed. My printer is an HP LaserJet 200 that is connected to the same network as my pc via wifi.

Until recently, I could scan to a network folder. Now it doesn't work anymore. When I try to setup the network folder via the printer's embedded web service, testing the network folder gives an error message: "Cannot connect to the network folder. Ensure the shared folder name is correct."

This is the message returned irrespective of whether the specified folder is in root (/) or in my home folder. The folder path is \192.168.1.nnn\foldername or \192.168.1.nnn\home\user\foldername where "192.168.1.nnn" is my PC's ip. I have tried it with forward slashes and back slashes. No difference.

Can anyone shed a little light? Surely it cannot be such a big problem ...