Although it could be a ton of different issues, sometimes it is due to the new router having different subnet such as 192.168.1.x and the node using a different subnet 192.168.0.x.
Could you confirm that your node was set to dhcp or static ip.
Some other troubleshooting you could do is to type ip a in terminal to see interface name and ip address if any assigned. This will confirm whether it is taking an IP address from ur new router.
If your node pc is connected via wifi the name could also be different and maybe thats why the node isnt able to connect.
If connected by LAN cable, you could plug that cable into another pc or laptop to see if internet works.
Share some more details about your setup and maybe someone could give better assistance. Are you able to view the node pc on a screen and does it have a keyboard etc. Are you totally locked out?