[WordPress Stats] Stats suddenly stopped working

My WordPress Stats plugin seems to have stopped working – it wants me to log in instead of just showing me the stats now, but when I try to log in it just sends me back to the wordpress.com login page again. (and I am actually logged in as admin on the wordpress on my site already, though that’s not on wordpress.com)

Not sure what happened, as I looked at the stats earlier today and it worked fine (this is post-3.0.1 update too, I had no problems with that).

Has something gone down elsewhere to cause this? If not, how can I get it back up again?