Kicked from server: cannot invoke net.minecraft.nbt.CompoundTag.m_128459_(String) because nbt is null

[GoogleCoder]

Hi, I'm trying to set up a server for the modpack GregTech New Beginnings (1.20.1). Since there is no server pack, I just copied the mods, config and other folders from my client installation to my server, then I removed the client-side mods. The server starts up fine and I can join but when it gets to 'Loading world' it gives me Connection Lost: internal exception java.lang.nullpointerexception cannot invoke net.minecraft.nbt.CompoundTag.m_128459_(String) because nbt is null and kicks me. It let me join a few times for seemingly no reason after over 8 hours of trying to make it work. Sometimes I can disconnect and reconnect perfectly fine for up to 10 minutes and then it suddenly breaks for no reason.

When I get disconnected, it still thinks I'm in the game and mobs kill my 'player' while my game isn't even open
Any help is appreciated

Logs:

Client: https://mclo.gs/T4SOejf

Server: https://mclo.gs/b42WzHx

Edited July 18 by GoogleCoder