Yum commands on RHUI client error: "Could not retrieve mirrorlist"

Issue

• RHUI client unable to get updates from CDS with the following error:

# yum check-update
Loaded plugins: katello, product-id, rhui-lb, security
Updating certificate-based repositories.
Unable to read consumer identity
Could not retrieve mirrorlist https://None/pulp/mirror/example_rhel5_protected error was
[Errno 4] IOError: <urlopen error (-2, 'Name or service not known')>
Error: Cannot retrieve repository metadata (repomd.xml) for repository: rhui-custom-10002. Please verify its path and try again