Download macOS button is missing when creating a new vm

Our corporate network blocks websites. The "Download macOS" is missing from my Free Systems. I worked with my IT group here and had them disable the software that blocks websites, and I'm able to see and use the "Download macOS." My guess is that we have to add a website to our whitelist so the button will appear. I want to be able to create VMs without getting my IT support involved.

What website should we add to our whitelist so that that button appears?