So this morning I was updating a couple plugins in one of my wordpress sites when I accidentally clicked another link in the middle of the process. When that happened I received the message “Briefly unavailable for scheduled maintenance. Check back in a minute.”. I waited a couple minutes but the error would not go away. After some snooping around I discovered that my .maintenance file had not been deleted from the sites main root directory. A simple FTP and deletion of the file got my site back online!
Hope that helps someone out!