I have been able to join other friend's world /others have been able to join my world with no issues up until around last week and this is still a recurring issue. We are able to connect with each other once, but if we need to leave and join back again, it will show that we are "Unable to Join World." My father, who writes software for computers, has looked at the PC to see if there is an issue with it but it is up to date on everything and does not seem to have an underlying issue. My friends have experienced this same issue and the only way it ends up working is through a lengthy process of trying to join over and over again. There is nothing wrong with our minecraft accounts that are linked to our xbox accounts, and this wasn't an issue until last week and it seems as if it is a bug for minecraft.