I have had the same problem happen to me many times and it still does. It only happens when as it said " Try to run more then one instance of the game". That means having two bad eggs pages opened on the same computer, even if they are on different websites. Simply close one page reload page and it should be fixed. I don't think it is necessary to restart computer but if the problem persists even after refreshing page then you might have to restart your computer. If you still receive same problem even when you have only one page opened then as MrDayCee said " It could be a simple detection problem from the game". I Hope this helps.
