Please follow the below template, it will help us to help you!
Expected Behaviour:
Fresh install. Expect Pihole to handle all DNS queries.
Actual Behaviour:
When I set my EdgeRouter Lite's (gateway 192.168.0.1) DNS to the PiHole (192.168.0.33) I lose internet connection. The PiHole does not appear to be blocking many queries.
I am not being very clear. I can set the router's DNS to use the PiHole. When I do that, the network devices lose internet access. I did have conditional forwarding set on to get client names. I turned that off and it did not make a difference. I do see individual IP address with conditional forwarding turned off.
I had a working PiHole for a long time and somehow the SDCard failed so I literally started from scratch. I never had these issue when I originally set up the PiHole six months ago? If you don't see something obvious it may be best for me to start over ... again from scratch. Maybe I messed something up during the install?
There is one abnormality in your debug log - when the log was run the Pi-Hole was not reachable via it's network interface. There may be a problem with the connection of the Pi to your LAN.
*** [ DIAGNOSING ]: Name resolution (IPv4) using a random blocked domain and a known ad-serving domain
[✓] mkt5857.com is 0.0.0.0 via localhost (127.0.0.1)
[✗] Failed to resolve mkt5857.com via Pi-hole (192.168.0.33)
[✓] doubleclick.com is 172.217.12.14 via a remote, public DNS server (8.8.8.8)
After you make this change, are you renewing the DHCP lease on the clients? This is the only way to push the new DNS information to them.
One minor item noted in the debug log - you have IP's listed in your whitelist. These do no good. If a device already has an IP, it won't query Pi-Hole for the IP. Devices only query Pi-Hole with a domain name that they want converted to an IP.
Wouldn't be my first choice. I would run pihole -r and select repair first, and see if that improves things. But, from the look of your debug log, the issue is not with Pi-Hole.