Clicking the red button should always do the work, if it's not working try to reload the page and clicking it again. If it still does not work, try to clear cookies from your history.
This should automatically sign you off your account.
What if I'm logged in the application? The red button doesnt work. :-/
If you use the official client to run the game, please follow the procedures below.
Сервис поддержки клиентов работает на платформе UserEcho