I'm using Windows 10 Pro
Hmm.. maybe try going to %appdata%, go back, go to LocalLow, Shrimp Plug Games, and delete everything in it. Then when you start the game, dont change your pfp or username. Also maybe try running the game as an administrator. It also could very likely be your modem firewall blocking the connection, but where I'm at right now I cannot test it. I believe the port I have for the game is 12250, if you want to try and port forward, if you know how. I'm new to the networking system I'm using for multiplayer, so it's probably doing things that I don't understand yet.