Pihole DHCP issue DNS issue

[deHakkelaar]

Make sure the DHCP server on the router is disabled and after you activated the DHCP service on Pi-hole, disconnect & reconnect network on clients or reboot them.

Plus this:

Why should Pi-hole be my only DNS server?

Reduced Ad Blocking Capability The main reason you should Pi-hole as your only DNS server is that you will see increased performance in the blocking of ads. If you have two DNS servers (Pi-hole and something else), your network clients may not always query Pi-hole for name resolution. If a query happens to be answered from a non-Pi-hole DNS server, your block lists will not apply (since that DNS server doesn't know about them). All Queries Need To Go Through Pi-hole First Since other DNS serv…