Strange bug I don't know how to fix when joining a server.

[AdinaTheFurscist]

I was trying to setup a server for me and my friend to play on, but then I ran into a bug where my tekkit legends client always crashed upon joining, I looked into the logs and all I could find was this. Does anyone know a fix to this? I've been trying to fix it for several hours and I can't seem to figure it out, much appreciated if you help me.

 

https://pastebin.com/AgxYDufw

[Munaus]

if nobody responds here, try going to our Discord

I can't help, as I have no experience with servers