I'm using the "Maintenance Mode" plugin (I already tried "WP Maintenance Mode" plugin, and got the same results), and the 'under maintenance' message only displays when I'm logged in. As soon as I log out, or visit the site from another computer, I see the website as normal. Maintenance mode is activated, and no matter what I set for "Access to blog front-end with capability (role):" I get the same backwards result. I've cleared the cache after every change, to no avail.
This is on a multi-site install with domain mapping.
Any ideas? Has anyone encountered this?