So, today a weird thing happened when I tried to login to an account with the stealth AB. The following thing showed up instead of my NPs on hand (below the login box):

I've tried restarting the program, rebooting my pc, logging in with other accounts where the NPs show up fine (with a different proxy) and then trying to login with this account and proxy again, and it just keeps happening.
The only thing that comes to my mind is that it may be the proxy, but why does this happen? Is there another solution, maybe?