When attempting to join a world, the game tries to connect but doesn't make it past the loading screen, and the connection times out. This is only an issue when attempting to join worlds on crossplay, as Featured Servers and Realms are perfectly fine and joinable.

On several different instances, the following happened:

• A friend of mine, using a Nintendo Switch, tried to join a world I hosted on mine. Couldn't connect, world didn't show up on his Friends tab despite having proper Microsoft settings.
• Attempted to join another friend's world, hosted on Switch, through the Friends tab from my Switch. Connection timed out.
• Attempted to join yet another friend's world, hosted on Switch again, through the Friends tab from my Switch; same results. Later attempted to join this friend's game, hosted on Windows 10, from my Switch again; same results.
• Yet another friend, using an Android device, attempted to join a world hosted from my Switch. World didn't show up on his Friends tab, and despite sending an invititation, his connection timed out.

While I personally initially thought the issue was exclusive to Switch, the different attempts and experiences with my friends, along with bug report MCPE-100211, lead me to believe the issue is present on all platforms.