If you use Mozilla Firefox and using Adobe Flash Player 10.3 you may see this popping up recently:
Translated it reads:
In order to better gaming experience, please update your Flashplayer to the latest version.
Click "OK" to leave the game update.
Click the "Cancel" to continue the game.
Hit "Cancel" and you can play normally with no issues if you are using 10.3.
If you hit "OK" it may cause issues like black screens and the game not loading.