THR has been up and running with no outage for the past several days. I think you are the victim of your own cache. Several other THR members reported the same thing.
The system was taken down for a planned upgrade about 6 days ago. If you (and the others) attempted to login during that outage, your cache may have captured the error message and is now refusing to let go.
Clear your browser's cache and try again. If that doesn't work, delete your THR cookie(s).