Unable to forward DNS requests to other NAMESERVERS on ERL

Hello,

I'm struggling with this and sor far I haven't being able to set the DNS forwarding, so any helo is really appreciated.

Here's my DNS config:

 forwarding {
     cache-size 150
     listen-on eth2
     listen-on eth1.10
     listen-on eth1.100
     listen-on eth1
     name-server 185.83.217.248
     name-server 5.9.49.12
 }

The eth1 is the interface where my hosts are located (under the subnet 192.168/16) , being my router set with  IP 192.168.1.1 .

However when I do a DNS query from any of the hosts using the router as a nameserver I simply got no answer:

dig @192.168.1.1 google.com

; <<>> DiG 9.10.4-P3-RedHat-9.10.4-2.P3.fc23 <<>> @192.168.1.1 google.com
; (1 server found)
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 27556
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

;; QUESTION SECTION:
;google.com.			IN	A

;; Query time: 14 msec
;; SERVER: 192.168.1.1#53(192.168.1.1)
;; WHEN: Sat Nov 12 13:17:03 CET 2016
;; MSG SIZE  rcvd: 28

The router firewall is currently allowing all UDP and TCP connections to port 53 (LAN represents the zone where the eth1 subnet - 192.168/16 is mapped):

show firewall name LAN-LOCAL 
 default-action drop
 rule 1 {
     action accept
     description "Allow established connections"
     state {
         established enable
         related enable
     }
 }
 rule 2 {
     action drop
     description "Drop invalid packets"
     state {
         invalid enable
     }
(...)
 rule 53 {
     action accept
     description "Allow DNS"
     destination {
         port 53
     }
     protocol tcp_udp

and the return connection is allowed on the  firewall:

show firewall name LOCAL-LAN 
 default-action drop
 rule 1 {
     action accept
     description "Allow established connections"
     state {
         established enable
         related enable
     }
 }
 rule 2 {
     action drop
     description "Drop invalid packets"
     state {
         invalid enable
     }
 }

With all of this set I honest see no reason why this isn't working.

Any help will be really appreciated!!