“Briefly unavailable for scheduled maintenance” message remainins after an automatic upgrade in wordpress

The problem:

Your WordPress site is showing “Briefly unavailable for scheduled maintenance” after an automatic upgrade has completed.

Solution: Remove .maintenance file

A file named .maintenance is placed by WordPress during an automatic upgrade to notify visitors that the site in under a short maintenance. If an upgrade fails or is corrupted, the file will remain in the WordPress folder and won’t get deleted.

To remove .maintenance file,

• Access your blog root directory via FTP or filemanager.
• Locate the file .maintenance.
• remove the .maintenance file from the blog root directory.
• Once you solve this problem, you may want to run the WordPress automatic upgrade again.