There's an issue with trying to join certain or all of your friends on your friends on your friends list whether you want friends to join your world or their own worlds, any world with the person you decide wants to join or joining them will not be able to let you join that player's world no matter how many new or old worlds the person creates for that friend. This issue doesn't apply to those that can join your worlds or join their worlds, but seemingly only a certain amount of people are affected to that they cannot join their friend's worlds and will result in a loading sequence before showing the "Unable to connect to world" text, thus being unable to joining the world of their choosing. May be a social bug since it affects those that have been added as friends or readded as friends or already have been added as friends for some time. Changing the world's multiplayer settings to "Invite only, Friends of friends, or Friends only" will still only result in the same issue of not joining the player's worlds regardless of the date of creation. But for the time being in 1.17.30 and so on if this issue isn't resolve players are unable to join the friend of their choosing and vise versa.