When joining a server too quickly after leaving another, the game will prevent you from joining another server by making you wait a minute to spawn into the server. However, at the end of this countdown, the game will simply display 'Please wait...' forever, and never actually allow you to begin playing.

If you leave the server and rejoin a long enough time later that you don't incur the penalty timer, you can join perfectly fine.

Additionally: The timer makes you wait a full minute even if you wouldn't have gotten it had you joined a second later. Instead of defaulting to a minute, it should make you wait as long as you would have had to wait to join a server without waiting to respawn.