cause: bind9 was listening on port 53

# find a service
sudo systemctl list-units --type=service | grep lxd

sudo micro /etc/bind/named.conf.options

#{
#listen-on { 192.168.2.22; 127.0.0.1 };
#listen-on-v6 { ipv-6-address; };
#}

# sudo mv /var/snap/lxd/common/lxd/networks/lxdbr0/dnsmasq.leases .
sudo systemctl restart snap.lxd.daemon