@Andrey Thanks for your reply. Do you think you could give any more information about what I should be looking at with the network setup? I have Tonfotos Desktop installed on a brand new Win 11 laptop. I have both the laptop and the phone connected to the same 2G WiFi - and both devices are sitting just feet away from the main router.
Today when I came to look at the issue again, my phone was showing the “connection error” so I had to delete and re-connect. The phone re-scanned for photos and returned a message that it had found a partial backup, and should it continue, which I agreed to. However now it won’t even upload 10MB successfully, it fails as soon as I click the “Start Backup” button. I rebooted the phone to see if that would help, but the result is the same.
I also tried switching both devices to the same 5G WiFi, but then they wouldn’t connect at all.