This is sort of a bug
(The host that you attempted to connect with is no longer present)
There are multiple posts about this on other sites but havent found anything on here. now I have found a way to fix the error above if the person you cant join hosts a game and you join them, then leave the game and go back into your session and invite them back the person that couldnt can join again. Easy fix doesnt require a network change please share this with other players