If you are getting the following message while updating some WordPress plugins, you can follow the below steps to fix it.
"Briefly unavailable for scheduled maintenance. Check back in a minute."
Whenever you update any WordPress theme or plugin, WordPress puts itself into maintenance mode. During this time, when you access your site, you will be notified by the“Briefly Unavailable” error message that means your website is undergoing an update at the moment and they should check back in some time. If the update is interrupted or fails, WordPress does not get a chance to take your site out of maintenance mode. In this case, you must manually change the update maintenance mode.
2. Find the root of your WordPress install
3. Locate the .maintenance file.
4. Remove that file.
5. Refresh your WordPress site