Some elements Plesk interface/websites hosted on Plesk are not loaded when Cloudflare's Rocket Loader is used

Symptoms

• The server's hostname resolves to a Cloudflare IP addresses
• When Plesk interface is accessed via the hostname (https://plesk.example.com or https://plesk.example.com:8443), the following issues may occur:
  •  In Tools & Settings > Backup Manager there are no Settings or Schedule buttons;
  • A blank page is shown in Domains > example.com > Databases or in Subscriptions > example.com > Databases;
  • Buttons Apply, OK, Cancel in all menus are greyed out;
  • Buttons in the top right corner are missing;
  • It is not possible to edit some files in Domains > example.com > File Manager
• Some elements of the hosted websites are not loaded properly
• The issue is not reproduced when Plesk is accessed via IP address: https://203.0.113.2:8443

Cause

Rocket Loader is enabled in Cloudflare dashboard. Cloudflare Rocket Loader cuts out several Plesk JS scripts 

Resolution

Disable Cloudflare Rocketloader.

Note: Cloudflare Rocket Loader compatibility was not properly tested with Plesk. It is not recommended to use it with Plesk because it will slow down the interface due to specifics in its source code.