"Could not proxy request: timed out" for 99% responses

On the "Rogue DNS" (ubuntu 16.04 ARM)

root@MyServer:/# iptables -A INPUT -i eth0 -p udp --dport 53 -j ACCEPT
root@MyServer:/# iptables -A PREROUTING -t nat -i eth0 -p udp --dport 53 -j REDIRECT --to-port 53
root@MyServer:/# /opt/scripts/dnschef.py --fakeip 192.168.1.42 --fakedomains *.hello.world.com --interface 192.168.1.42 --nameservers 8.8.4.4 --logfile=/var/log/dnschef.log -q
[*] DNSChef started on interface: 192.168.1.42 
[*] Using the following nameservers: 8.8.4.4
[*] Cooking A replies to point to 192.168.1.90 matching: *.hello.world.com
[00:25:08] 192.168.1.66: proxying the response of type 'A' for www.google.com
[00:25:11] 192.168.1.66: proxying the response of type 'A' for www.google.com
[00:25:12] 192.168.1.66: proxying the response of type 'A' for www.google.com
[00:25:15] 192.168.1.66: proxying the response of type 'A' for www.google.com
[00:26:22] 192.168.1.66: cooking the response of type 'A' for www.hello.world.com to 192.168.1.42
[00:26:25] 192.168.1.66: proxying the response of type 'A' for www.google.com
[!] Could not proxy request: timed out
[00:26:30] 192.168.1.66: proxying the response of type 'A' for www.google.com
[!] Could not proxy request: timed out
[00:26:37] 192.168.1.66: proxying the response of type 'A' for www.google.com
[!] Could not proxy request: timed out
[00:26:42] 192.168.1.66: proxying the response of type 'A' for www.google.com
[!] Could not proxy request: timed out
[00:26:48] 192.168.1.66: proxying the response of type 'A' for www.google.com
[!] Could not proxy request: timed out
[00:26:53] 192.168.1.66: proxying the response of type 'A' for www.google.com
[!] Could not proxy request: timed out
^C[*] DNSChef is shutting down.

On the client who test the DNS :

user @ machine  ~
└─ $ ▶ host -t A www.google.com 192.168.1.42
Using domain server:
Name: 192.168.1.42
Address: 192.168.1.42#53
Aliases: 

www.google.com has address 172.217.17.68
user @ machine  ~
└─ $ ▶ host -t A www.google.com 192.168.1.42
;; connection timed out; no servers could be reached
user @ machine  ~
└─ $ ▶ host -t A www.hello.world.com 192.168.1.42
Using domain server:
Name: 192.168.1.42
Address: 192.168.1.42#53
Aliases: 

www.hello.world.com has address 192.168.1.42
user @ machine  ~
└─ $ ▶ host -t A www.google.com 192.168.1.42
;; connection timed out; no servers could be reached
user @ machine  ~
└─ $ ▶ host -t A www.google.com 192.168.1.42
;; connection timed out; no servers could be reached

Hmm, this appear when i add the dnschef server in the router's DNS list and enable DNS Relay on it, but their is not any line in dnschef about connexion from the router's ip address.
In iftop i can see the connexion to the google dns server used in this test (8.8.4.4).