I get a pop-up window asking me to log into my account but no field to enter my details appears. It seems to attempt to load (or at least the background momentarily changes to grey), but the only things visible are 'Sign in with API key' and 'Trouble signing in?'. I've tried to use the tab key to see if I can find an invisible field but this doesn't work.

I am running a Windows 8.1 machine and have Bitdefender installed but this does not appear to be blocking anything.

Skripting of Java Applets is deactivated but activating has no effect.