Firewall problem

Hi,
Please allow me to disturb you, I am facing exactly the same DNS issue on pi-hole but I don’t know where to start. On my lab I have a Sophos XG firewall and my Internet service provider is Vodafone (UK).
In this case where can I go to sort out this DNS resolver issue please.

Regards,
Ben

Please upload a debug log and post just the token URL that is generated after the log is uploaded by running the following command from the Pi-hole host terminal:

pihole -d

or do it through the Web interface:

Tools > Generate Debug Log