Based on KB:
https://access.redhat.com/solutions/1583183
We might need to add more CDN host for fully Insights function:

https://cert.cloud.redhat.com:443 [needed for Inventory upload and Cloud Connector connection]
https://sso.redhat.com:443
https://console.redhat.com:443 or https://cloud.redhat.com:443

The real story:
Customer apply firewall based on this Satellite manual and fail to use Insights in Satellite. That might be a bad impact.

Reported by: rh-ee-hsiwang

https://access.redhat.com/documentation/en-us/red_hat_satellite/6.11/html/installing_satellite_server_in_a_connected_network_environment/installing_server_connected_satellite#annotations:a0b13fa2-1277-449d-b90f-89014fe979e8