How to login into the Red Hat Support Plugin for RHEV through a proxy server?

Issue

Red Hat Enterprise Virtualization Manager system is located behind a proxy server. When login to the Red Hat Support Plug-in fromRHEV-M WebPortal`, following message reported:

Unable to reach access.redhat.com from <rhevm-hostname>. The Red Hat Support Plug-in for RHEV is will be disabled until connectivity is restored

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