I got the response: "Facebook Will Be Back Soon. Facebook is down for required maintenance right now, but you should be able to get back on within a few minutes. In the meantime, read more about why you're seeing this message. Thanks for your patience as we improve the site."
I captured a screenshot of the Facebook message, which you should be able to access at this link
Is Facebook down for you, too? I doubt it. See the screenshot below, which you can click to enlarge.