If it automatically logs you into an account, click the
icon in the upper-right corner and click "Yes" when it asks you if you
want to quit. It should display the homepage. Now click on "Play", and
it should display the login screen. Next time, don't check the "Remember
me" box if you wish to be asked to login to your account(s) every time
you open Tanki Online.
Customer support service by UserEcho