One of the most annoying error in WordPress is the ‘Scheduled Maintenance’ message a Webmaster gets after an automatic upgrade has completed.
This problem is mainly caused by a failed automatic upgrade or an interrupted update process. So each time a visitor tries to visit your home page, he/she will get the following message:
Briefly unavailable for scheduled maintenance. Check back in a minute.
In fact, each time WordPress is automatically updating its core files, themes or plugins, the blog will be marked as ‘under maintenance’.
To fix this problem : remove .maintenance (hidden) file, located in your blog root directory and the site will come back.
You may want to run the WordPress automatic upgrade again after resolving this problem.
