BMC4 server not letting me join

Hello, i recently got a server with bisect and it's my first time doing something like this, but i just wanted to play Better Minecraft 4 with some friends. I cannot even load into the server without my game crashing and telling me this: "The game crashed: unexpected error
Error: java.lang.NullPointerException: Cannot invoke "net.minecraft.client.player.LocalPlayer.m_150109_()" because "this.f_105189_.f_91074_" is null" ive been practically pulling hair out over this since last night because i had mod issues, fixed those and now i cant figure out what this means for the life of me