Wont let me join my friends world or they cant join me. When i try to join there or mine it says "unable to connect to world" it will try to connect for 15 seconds and then give me this error.

I am un able to play with my friends and they cant play with me. Ive tried looking this problem up and tried everything. When clicking to join it will load for 15 seconds and the give the dirt screen with error message "unable to connect to world". This will happen every time I try join my friends. Same thing for them when they try to join me