Client Discovery Problem

Hello, 

In my current setup, I'm using nextdns cli, with pihole, 

pihole listen dns traffic from standart udp53

pihole forward dns traffic to nextdns cli via 127.0.0.1:5055

everythings are working great. but client discover looks not working, And can't see log differentiation over nextdns dashbord, 

I'm getting following error, when run "nextdns discovered" in "nextdns log" 
Dec 19 13:12:33 raspberrypi nextdns[549]: Control client connected: &{{0x240e190}}
Dec 19 13:12:33 raspberrypi nextdns[549]: Control client sent event: &{{0x240e190}}: discovered(<nil>)
Dec 19 13:12:33 raspberrypi nextdns[549]: Control client disconnected: &{{0x240e190}}

DHCP working over pihole, I copy the logs via scheduled script to under
"/tmp/dhcp.leases"

My configuration

control /var/run/nextdns.sock
config ------
cache-size 0MB
report-client-info true
timeout 5s
auto-activate true
cache-max-age 0s
max-inflight-requests 256
setup-router false
log-queries false
hardened-privacy false
listen :5055
max-ttl 5s
discovery-dns 127.0.0.1
mdns false
detect-captive-portals false
bogus-priv true
use-hosts true

nextdns discovered
{
    "dhcp": {
        "client1.": [
            "192.168.1.70"
        ],
        "client1.local.": [
            "192.168.1.70"
        ],
        "client2.": [
            "192.168.1.50"
        ],
        "client2.local.": [
            "192.168.1.50"
        ],
        "iphone1.": [
            "192.168.1.60"
        ],
        "iphone1.local.": [
            "192.168.1.60"
        ],
        "iphone2.": [
            "192.168.1.62"
        ],
        "iphone2.local.": [
            "192.168.1.62"
        ],
        "iphone3.": [
            "192.168.1.61"
        ],
        "iphone3.local.": [
            "192.168.1.61"
        ]
    },
    "dns": {
        "_dns.resolver.arpa.": null
    },
    "hosts": {
        "ip6-allnodes.": [
            "ff02::1"
        ],
        "ip6-allrouters.": [
            "ff02::2"
        ],
        "ip6-localhost.": [
            "::1"
        ],
        "ip6-loopback.": [
            "::1"
        ],
        "localhost": [
            "127.0.0.1",
            "::1"
        ],
        "localhost.": [
            "127.0.0.1",
            "::1"
        ],
        "localhost.localdomain.": [
            "127.0.0.1",
            "::1"
        ],
        "raspberrypi.": [
            "127.0.1.1"
        ]
    }
}