For starters, this goes in the help board ^^
Anyways, are you using the new login page? When you click, 'Play Game' you will be able to login with your details. If it's successful, a text saying 'You must keep this open to play' will pop up. Once that's out of the way, try logging into the game itself. Keep the tab open the entire time.
Finally, if it has been over a year or so and you haven't logged during that time, your account probably got deleted.
Hope this helped!