toolbox fails to start in OCP 4.x using HTTP/HTTPS Proxy

Issue

Even if HTTP_PROXY and HTTPS_PROXY are set properly, toolbox still fails with following errors:

Trying to pull registry.redhat.io/rhel8/support-tools...ERRO[0060] Error pulling image ref //registry.redhat.io/rhel8/support-tools:latest: Error initializing source docker://registry.redhat.io/rhel8/support-tools:latest: pinging docker registry returned: Get https://registry.redhat.io/v2/: dial tcp 104.103.100.204:443: i/o timeout
Failed
Error: error pulling image "registry.redhat.io/rhel8/support-tools": unable to pull registry.redhat.io/rhel8/support-tools: unable to pull image: Error initializing source docker://registry.redhat.io/rhel8/support-tools:latest: pinging docker registry returned: Get https://registry.redhat.io/v2/: dial tcp 104.103.100.204:443: i/o timeout