How to configure Subscription Asset Manager to use a HTTP proxy for clients to access the CDN?

Issue

• Subscription Asset Manager (SAM) clients are unable to get content when a HTTP proxy sits between SAM and the CDN.
• Running yum update on SAM clients encounters the following error:

[root@sam-client ~]# yum update
Loaded plugins: product-id, refresh-packagekit, subscription-manager
Updating certificate-based repositories.

Please use yum-config-manager to configure which software
repositories are used with Red Hat Subscription Management.

https://sam.example.com:8088/content/dist/rhel/server/6/6Server/x86_64/cf-tools/1/os/repodata/repomd.xml: [Errno 14] PYCURL ERROR 22 - "The requested URL returned error: 502"
Trying other mirror.
Error: Cannot retrieve repository metadata (repomd.xml) for repository: rhel-6-server-cf-tools-1-rpms. Please verify its path and try again

• Clients are able to get content from the CDN via the HTTP proxy if they don't use SAM.