Online Not Working

[Darkpixel797]

Whenever I try to play online with my friend the same thing happens, whether its him or me hosting, the host gets a "null left the game" message and the joiner gets an empty bugged lobby that looks like the png attachment and if the joiner tries to type anything in chat they get an error message. I have the correct port forwarded and he doesn't but the same thing happens no matter who tries to host. I also attached my forge.log, I am incredibly confused as to what's happening because I got online working with a different friend a few months ago first try without a port forward, this program seems to defy all logic.