Problem with URL Filtering

I have a problem accessing a certain GitHub URL. For example, when I try to update Pi-hole the address objects.githubusercontent.com cannot be resolved:

At first, I thought it was an issue with Pi-hole itself or with openDNS, its upstream DNS server. But I realized that this is not the case, it happens to me when I try to download something from GitHub.

Investigating, I have seen that, for example:
- If I temporarily disable the blocking, the Pi-hole blocking still does not resolve the URL.
- If I ping from outside my LAN, it does respond:

In Pi-hole I have put the URL on a whitelist. In Sophos, I have tried to do the same, I think I have done it right, but the address is still not resolved.

Any suggestions?

Kind regards,

Albert