Site update sticks with “Briefly unavailable for scheduled maintenance. Check back in a minute.” or “The website is undergoing scheduled maintenance” message.

Connect using FTP and delete the .maintenance file in the root directory.

Other checks

Are you sure the message being shown isn’t your own dummy message for a site you’ve haven’t finished creating yet?!!

The wordpress updates Page

This is the URL for the updates page

http://mysite.com/wp-admin/update-core.php