By default, CDN edge server will always fetch content from origin using HTTP protocol.
Origin Policy is made available to allow CDN resource in using different HTTP/HTTPS protocol for CDN edge server to fetch content from origin.
There are three options for Origin Policy:
HTTP - connection between edge and origin ALWAYS uses HTTP. This is the default value.
HTTPS - connection between edge and origin ALWAYS uses HTTPS
AUTO - connection between edge and origin based on the request from visitor (HTTP or HTTPS)
You may configure Origin Policy under CDN Resource page, by enabling "Advanced Settings".