My clients aren't getting my DNS settings, just the gateway ip

I am setting up a PiHole as a DNS server, but for some reason when I configure the DNS to manual and add my DNS servers, the clients keep the gateway as their DNS provider. Am I missing a configuration? Do I need to reboot my clients?

Hello,

Please add DNS server (pihole) in Network > LAN > Advance, it will be offered to the LAN client through DHCP server.