Occassionally WordPress has a hiccup while doing plugin updates, and you’ll see a message that just won’t go away:
Briefly unavailable for scheduled maintenance. Check back in a minute.This typically happens when you navigate away from the plugin update page during the update, which prevents the plugin from being completely updated.
The solution is simple: delete the .maintenance file in the root of your website. You can do this using the rm command (remove, or delete) in the terminal:
rm /var/www/html/yourdomain.com/.maintenanceThat’s it! You’re done!