Have you tried accessing the login page through another browser?
Google Chrome & Firefox seems like one that most users use to try and get the game up and going.
Also, waiting a little while after logging into the page can also help.
You can also try and logging into the tab through your phone and see if that helps also?
Also, keep in mind that if you changed your user, it can take awhile before the server recognizes the change and that you're able to sign in with the new user as well...
Lastly, make sure it hasn't been about a good while or so since you last played the game. The server might've eaten the account due to inactivity.
Nej problem, Glad it works ~!