Wont let me join my friends world, but only for one world and its copies

I go to join the world and it will either say unable to join world or it will sit on the locating server screen until i exit the app. It shows me loaded in the game for them but i am only half in. We have tried on and off wifi, we've unfriended and refriended each other, i uninstalled and reinstalled, i signed out and back in, nothing has worked. It lets me join public servers and other servers of my friends, just not this one in particular. We've been on this server for about a month and it's been fine, and everyone else can still join the server except me. It started not letting me in about 3 days ago