u/DisasterEquivalent43

I have a 1.20.1 modpack on Curseforge with 2 friends and I added the Better End forge mod. One of my friends was able to join without any problems but the other would join for a few seconds then crash every time. I tried deleting the mod from the modpack and playing without it but then my friends would get this error: internal exception java.lang.nullpointerexception can not invoke "net.minecraft.nbt.compoundtag.m_128459_(string). I went into the modpack files and searched up and deleted any files that had Better End in it but the error still occurred. We also haven't even been to the End dimension yet so I'm not sure what's causing this. Now, I'm unsure on how to avoid this error and would appreciate any help I can get.