I hafta log in, then post, then relog in to confirm my post, and editing posts after I've posted em seems like an impossible loop (see loggin in then relogging in). Using Safari. I can easily not use Safari, just thought I'd let you know.
that's happened to me once or twice over the years when I got a new computer and it didn't recognize me. once you log in, be sure to tick the "stay logged in" or "remember me" box or whatever it's called (I'm afraid to log out to see what it's actually called!)