unable to connect to world error

me and my friends have this world we have been playing on, sometimes my friends can join and sometimes they cannot. It is very frustrating because i have tried everything to fix it: re added my friends on xbox, re installed minecraft, disabled my fire wall, check my xbox settings, updated my drivers, nothing works. It shocks me that microsoft is one of the biggest companies in the world but they cant even fix bugs in a game. This bug has been going on ever since bedrock was released and its already in the nether update with still no fixes. PLEASE FIX THIS