Doing WordPress upgrades or just a theme/plugin version in WordPress can be said to be horrified – a delicious horror. We already know in the process then the site will go into maintenance mode and can not be used normally.
The problem is sometimes the process is not completed update-done, maybe the host specs are not good or there is a glitch forgot to be disabled maintenance mode.
This is what happens to one of my WordPress installations, wait a long time but not done right away and finally, this error page always appears:
Briefly unavailable for scheduled maintenance. Check back in a minute.
How is the solution? Directly access your WordPress installation location, can use FTP or SSH, and check-in its root directory (which is at the same level as WP-config.php and robots. txt) whether there is a. maintenance file. Just delete it. Then access to your website and its administration will be normal again.
What is the maintenance file above? This file is used by WordPress to indicate that the CMS is going into maintenance mode, it should be removed automatically when it finishes the process.