Sometimes your server will get locked up before completing an update task, activating a new theme, or installing a new plug-in.  What happens is WordPress temporarily will place your site in “Maintenance Mode”.  If you go onto a WordPress website that shows a page with the message “Briefly unavailable for schedule maintenance.  Check back in a minute.”  This is what is happening.

Occasionally, you won’t be able to get out of maintenance mode.  If this happens, your site won’t come back up.  First, remember the last task you were working on, chances are it did not update or install properly so you’ll have to remove or repeat the task.  Second, go to your WordPress root folder through FTP and delete the file “.maintenance”.  This will get your site out of maintenance mode.