Are you running adguard home? Is it installed on a VM on the LAN or on OPNS?Then, what settings you have in OPN Settings > General?What settings you have in Adguard Settings > DNS Settings ?Finally, are you running Unbound or DNSMasq, which settings on them?I can share my settings that work. I have Adguard Home on OPN (plugin), with Unbound.Unbound is running on 5353 on OPNS. AGH has 192.168.5.1:5353 for it's DNS server. That is my OPN LAN ip and the port for Unbound. In OPN Settings > General there is no DNS set and "Do not use the local DNS service as a nameserver for this system " is enabled.That causes OPN to give DHCP clients it's own ip and port 53 by default as DNS server. DNS queries are received by ADG on port 53 and sent to OPN Unbound on port 5353.I have a couple of firewall rules for stray clients but you should get the basic setup going first.