A free membership allows a player to play only 20 games simultaneously and when this limit is reached, new games cannot be started until the number drops below 20.
Higher membership levels solve this problem in the following way:
(hide) If you are waiting for your turn, click on "change" next to the "refresh" on the main page, then set refresh the page to 30 seconds to get your turn to move displayed faster. (Servant) (show all tips)