Unable to connect to HP8100 after changing router

[NH1233445676879]

My printer was previously connected to my home network via Ethernet (and before that by WiFi) with an IP address in the 192.168.0.xxx range. I just changed my ISP which means I now have a new router and the IP address range is 192.168.1.xxx, and since then I have been unable to connect my printer other than by USB. The printer will connect to the network, either by cable or WiFi, which I know because I can "ping" it, and also see it on the list of connected devices on my router's web page, but it does not show up when I expand "Network" under Windows Explorer, and I cannot add it as a printer. The new router is a Linksys Smart WiFi one, and my PC has network discovery enabled, network set to private, and indeed I can see other network devices in Windows explorer.

[NH1233445676879]

One thing I forgot to mention: I tried using the HP Smart app, with the printer connected by Ethernet, and this did indeed detect it and show it as online. However, when I selected it to complete the setup it then told me I should select a different printer, and the status changed to offline. This happened repeatedly.

[Valsimot · Accepted solution]

Turn the printer ON, remove the ethernet cable, press and hold the wireless and cancel button for 3 seconds, that should reset the network. Connect the ethernet cable wait a minute, press the Resume button then press wi-fi button the printer should print a network config sheet, check if the IP address is within your range 192.168.1.xxx

[NH1233445676879]

Yes, I did all of that, and as I said, the printer has a valid IP address in the correct range which was shown in the router's "connected devices" and also on the network configuration page printed as you described. If I run the old "HP Officejet 8100" software that too finds the printer under the correct IP address and says it's installed it - but the printer doesn't print anything. I tried setting it up as before on the old router (but with the old IP address range, I was unable to change that) and that worked, so plainly it's some sort of configuration or communication issue but I can't work out what; all other devices communicate fine through the new router.

Since then I've tried completely uninstalling and reinstalling the printer software (it didn't help), and I've run Wireshark while running HP Smart which confirms that messages are being exchanged between the PC and the printer (thereby confirming the IP address as well), and I've tried disabling the antivirus and firewall to no avail. I've also tried loading the latest software package for that printer from the HP website and running that, which gives the same results as the original HP 8100 software (not surprising since I believe it's essentially an updated version of the same thing).

I even tried installing the printer on a machine running Ubuntu, and again got a similar result - printer identified, installation apparently OK yet unable to print.

[NH1233445676879]

I thought I'd done what you suggested to reset the network, but maybe I didn't hold the keys down for long enough or something. Anyway, resetting it again seems to have got things working at last - though I'm not sure why since the IP address etc were right before I did anything. Anyway, thanks for the help.