Adding on to what has already been said, make sure your proxy server is off. You can check your internet settings and you can change this. But as stated above, if your characters are more than 16 characters long, then no matter what you do, the game will not let you play. You would have to wait until registration is opened. Also, trying out Chrome / Firefox can also help as Shurtle suggested. Another thing you could try is logging in from your cellular device if you have one.