Pi hole not serving DNS to client

[jobewan]

Please follow the below template, it will help us to help you!

Expected Behaviour:

-Pi OS 64 bit (Debian GNU/Linux 10: Linux Rasberrypi 5.4.51-v8+ #1333)
-4GB Rasberry Pi Model B; 32GB Class 10 SD card

Actual Behaviour:

nothing is happening; I point my MacBook (Catalina) to the reserved IP for the Rasberry and DNS stops working altogether; flushing the DNS cache has no effect; I can ping the Rasberry from my Macbook and vice versa; I can run nslookup on the Rasberry against known domains; putting DNS back on the Macbook restores DNS resolution

Debug Token:

https://tricorder.pi-hole.net/ed1xk08gt0

[jfb]

You have a connectivity problem on the Pi:

*** [ DIAGNOSING ]: Networking
[✗] No IPv4 address(es) found on the eth0 interface.

[✗] No IPv6 address(es) found on the eth0 interface.

[i] Default IPv4 gateway: 192.168.1.254
   * Pinging 192.168.1.254...
[✗] Gateway did not respond. (https://discourse.pi-hole.net/t/why-is-a-default-gateway-important-for-pi-hole/3546)

[i] Default IPv6 gateway: fe80::c289:abff:feb9:9620
   * Pinging fe80::c289:abff:feb9:9620...
[✗] Gateway did not respond. (https://discourse.pi-hole.net/t/why-is-a-default-gateway-important-for-pi-hole/3546)

   Oct 11 10:38:16 dnsmasq[814]: warning: interface eth0 does not currently exist

[jobewan]

The Rasberry device in this context is connected wirelessly; forgive my ignorance, but is that the issue, or an issue? It's my understanding that eth0 is the wired interface.

[jfb]

Run pihole -r and select the reconfigure option. Then select the active interface and IP.

[jobewan]

Ugh. ACH! I saw the answer in my mind's eye the instant I read your response. Thank you for being helpful rather than . .