Failed to setup netplay sockets

First of all, I want to say that this seems like the emulator I’ve been looking all over for! I want to play ‘couch’ co-op with a single player game (passing the controller) and with the ability to switch p1 and p2 i think this emulator can do it!

I’ve been trying to launch with a friend and we’ve tried everything we can think of. Port forwarding in the router, shutting off firewalls, different games, running as admin etc and we continously get the same error 'failed to setup netplay sockets"anyone have any suggestions?