I have Sky broadband and the new SkyQ router which does not allow DNS changing, so I have to configure my clients manually to use Pihole as DNS, which is working fine and they all have working internet connections and tail pihole.log shows them querying Pihole for DNS, but Pihole is just forwarding every query to 1.1.1.1 (Cloudflare that I have set in Pihole DNS settings), absolutely nothing is being blocked - I even went as far as to rebuild the entire Rasp Pi from scratch without any luck
Pihole is running on the Original Raspberry Pi Model B, it is running Raspberry Pi OS Lite (buster)
EDIT - Just noticed my Blocked Domains list was showing 0 (It had over 400,000)
I ran the update gravity setting and it returned this:
[i] Neutrino emissions detected...
[✗] Pulling blocklist source list into range
[i] No source list found, or it is empty
[i] Building tree...
[✗] Unable to build gravity tree in /etc/pihole/gravity_temp.db
Error: no such table: main.gravity
[i] Number of gravity domains: 0 (0 unique domains)
[i] Number of exact blacklisted domains: 0
[i] Number of regex blacklist filters: 0
[i] Number of exact whitelisted domains: 0
[i] Number of regex whitelist filters: 0
[✓] Cleaning up stray matter
[✓] DNS service is running
[✓] Pi-hole blocking is Enabled
EDIT 2 - OK it seems to be working now after running pihole -g -r