Hello!!
After going around in circles, doing many tests and trying various configurations both on the Pi-hole and on the Sophos, it is clear to me that there is something in the firewall that is blocking the domain (and the subdomains) *.githubusercontent.com.
The last test that confirms this is the ping from Sophos itself to the domain, as you can see in the screenshot, this time I do get a response:
As I said, I have done several tests, such as adding the domain as an exception, fine-tuning the web filtering policy, fine-tuning the internet browsing policy, adding the FQDN as an exception, changing the DNS offered by the DHCP... But nothing works, I am quite confused...
What else could I try?
Kind regards!!
Albert.
Hello!!
Finally I've resolved the issue:
The culprit was a third-party threat feed, the CiberHost_UK, the domain .githubusercontent.com is categorized as malware:
Kind regards.
Albert