You address (192.168.231.165) is simply not allowed to make a query to the server as it is not in the trusted ACL.
allow-query { trusted_subnets; }; acl trusted_subnets { local_nets; vpn_subnet; synthnassizer_subnet; dsa_office_subnet; skails_dns; synthnassizer_dns; dsa_dns; m2g_dns; }; acl outbound_subnet { 192.168.231.0/24; // Your address is matched here };
You can check this doc on allow-query
option in config.