This article applies to Plesk Panel Maintenance Mode
Using the Maintenance Mode in Plesk Panel allows you to display a 503 error page while the website is offline.
Tip: Use the File Manager to open and edit the error page to your own requirements. Instead of the standard "Service Unavailable" message, you can create your own message like "The site is temporarily down for maintenance, it will be up again soon."
Login to your Parallels Plesk Panel.
Click on the Domains link on the left panel.
Click on the Open in Control Panel link for the relevant domain name.
Click on the Website & Domains tab.
Click on the Show Advanced Operations option at the bottom of the page.
Click on the Website Maintenance Mode icon.
Check the box Switch on the maintenance mode for website and press the OK button, the website will now disply a 503 Service Unavailable message to visitors.
Maintenance mode is now enabled for your website.
To turn maintenance mode off uncheck the box Switch on the maintenance mode for website and press the OK button, the website will now return online.