Lately I've been getting this message when I try to login to several of my WordPress sites:
—ERROR: Cookies are blocked or not supported by your browser. You must enable cookies to use WordPress.—
Now, here's the problem. First of all, I have my cookies enabled. But what's even weirder is that if I attempt the login once or twice more it eventually lets me in.
This has been going on more or less since 3.7.