There are a couple things that I can think of, but I would like to address the new router situation first.

Whenever you have to upgrade or replace your router, if you don’t have a reason to change the SSID and password, simply configure the new router with the same information. This way devices will automatically reconnect to your network. Those that don’t would simply need a reboot to acquire a new IP address.

Secondly, unless you absolutely need to, factory resetting Sonos speakers/devices wipes important information and settings, that support would need if you have to call them. A factory reset should be a last resort.

Have you checked for firmware and app updates recently? If you have not applied them, you should do that then check to see if your issue has been solved.

After the above, you could unplug the Port, connect it to Ethernet and power it back up. That may help it move to the new network.

If the above have not resolved your issue, are there any error messages? Is PANDORA the only service that is not working?