I'm running a server through a host for me and a couple of friends. The other day, one of us got suddenly kicked out of the game. Since then, whenever they try to log in, they crash the whole server. However, my other friend and I can log in and play just fine, even in the area where our currently bugged friend got kicked, which is in the middle of our base.
We've tried deleting their playerdata but it didn't work. I attach the crash reports of the last time they tried to log in.
The server is running a pretty heavy modpack (Modified Cobblemon Plus), as a piece of extra info.