I just tried to log in. It is not telling me "Bad Gateway" but for some reason that I don't know it is not letting me log into my account. These things happen, not just with aa.com. All I can say is try in a few hours, and again tomorrow if it still doesn't work.
They're doing a promotion for all AAdvantage members. Maybe that's slowing things down? There is a giveaway for all that have status from Gold all the way to CK.