Hi Cohen, the error is in the script FizzySteamworks.cs. I have tried what you advice above but the problem persist, if I just import any other version of Fizzy while one version is in the project, it would not go through. If I just delete the Fizzy folder and import, only the 4.0 or above work, 3.0 and 2.7 would have ServerDisconnect error.
Anyway, my issue is my friends do have the Join button to join but they would not go into the lobby, their games hang out in Main Menu and all UIs disappear. I initially thought it just being slow but in the end, they never connected. And yup, we all “playing” Spacewar, I guess that just Steam’s technical tools for us to test the transport.