Enabeling "Hide IP address"

Safari 15.5 has an option in Preferences/Privacy to "Hide IP address". When turned on, this has led to some web-sites not loading at all or only loading partially. independent.co.uk is an example of a site that does not load. Turning this option off makes the page load. Opening the Network tab in the Web Inspector (alt+cmd+i) panel reveals that moatads.com and doubleclick.net does not respond and hangs the loading of the page when this option is on. Testing the same thing on a different network does not give the same result. This makes me think that this issue is caused by the network configuration of my first network. How would I go forward to investigate what is the cause of this issue? Are there specific requirements for the network configuration to enable this option?