Let’s say that you accidentally closed your browser tab in the middle of an automatic update, or you were trying to automatically update a huge number of plugins/themes at once. And unfortunately, there’s a compatibility problem that causes a glitch. As a result, you persistently see this message when you try to visit your site:
Briefly unavailable for scheduled maintenance. Check back in a minute.
When WordPress puts itself into maintenance mode, it does so by creating a file named “.maintenance” in the root folder of your WordPress site. This is the same folder that contains:
wp-admin folder
wp-config.php
To fix the WordPress stuck in maintenance mode problem, you’ll need to connect to your server via FTP and delete that file. Once you’ve connected to your site via FTP, find the “.maintenance” file in your root folder and delete it.
You site will load now!