Constant errors when a friend tries to join me, and I try to join them.

Hello. I have an issue that has been persistent for around a year now. On my Xbox 1. I bought Minecraft, and for my iPad . All of a sudden. I get "unable to locate world. Unable to connect to host, unable to connect to world" Every time I want to join my friends world. He has multiplayer enabled yet we both get these alerts. Even on a completely different device this happens. I deleted the game, deleted the cache, restarted the game, restarted my console, and it still will not work. I paid for this game so it needs to be fixed. We even tried the wither flower method the community promised would work yet it didn’t.