In this tutorial, I will explain how to fix Maintenance Mode Following Upgrade in WordPress. When you are upgrading your WordPress to the lasted version, then WordPress will automatically create a .maintenance file. The .maintenance file contains the message like “Briefly unavailable for scheduled maintenance. Please check back in a minute.”
Sometime the .maintenance file may not have been removed properly, that’s why you are getting this error when accessing the frontend website.
Follow the below steps to fix this issues.
Step 1) Log in to your website using your cPanel and open file manager.
Step 2) Delete the .maintenance file, which will be found in your site root. See the below screenshot.