Can't join a world with 3 people

I been having this problem  for a month now where my friends can't join my world if their 3 people inside the world and the same for me If I try to join their game but I can join severs and play inside and join people that only has 2 people inside their world but when their 3 it doesn't  let me join and it the same for all my friends please fix this cause we all can't play inside are survival  world do to thia bug . 

 

It continues  to say the same thing  and we has all try everything  to fix this world this is 5 of us and we can not play pass 3 players and all can't play together so please look into this bug .