Getting stuck in maintenance mode sometimes occurs when performing some WordPress upgrades. After performing a WordPress version upgrade this error message presents itself:
“Briefly unavailable for scheduled maintenance. Check back in a minute.”
And it appears that nothing else can be done in the Dashboard and the web site cannot even be viewed.
If you find yourself in this predicament the quick fix is to delete the file called “.maintenance” in the root folder of the WordPress site. Use terminal to securely log into your site’s server. In the root directory issue this command:
sudo rm .maintenance
When this is done your WordPress web site returns to functionality.