The same thing happened to me the other day as well. I posted about it, but no one else replied that it was also happening to. I guess we missed each other's posts.
I was told to clear the cache and cookies, but didn't get a chance to do so. I checked it just now, "just in case," and whaddayaknow, it's working again. So it couldn't have been the cache and cookies or it wouldn't be working now. :-)