ping request não encontrou o host. Por favor, verifique o nome e tente novamente

Question

Eu comprei um vps e de alguma forma eu configurei os servidores de nomes errado no CentsOS 7.

Eu instalei bind e segui as instruções neste link link .

Quando eu ssh o servidor e ping o host eu recebo este resultado:

ping example.com
PING example.com 56(84) bytes of data.
64 bytes from mail.example.com : icmp_seq=1 ttl=64 time=0.024 ms
64 bytes from mail.example.com : icmp_seq=2 ttl=64 time=0.053 ms
64 bytes from mail.example.com : icmp_seq=3 ttl=64 time=0.052 ms
64 bytes from mail.example.com : icmp_seq=4 ttl=64 time=0.047 ms
64 bytes from mail.example.com : icmp_seq=5 ttl=64 time=0.276 ms
64 bytes from mail.example.com : icmp_seq=6 ttl=64 time=0.053 ms
64 bytes from mail.example.com : icmp_seq=7 ttl=64 time=0.073 ms

e quando eu verifico nslookup eu recebo este resultado enquanto sshing o servidor:

nslookup example.com
Server:         26.21.98.42
Address:        26.21.98.428#53

Name:  example.com
Address: 1.1.8.8

named.conf:

//
// named.conf
//
// Provided by Red Hat bind package to configure the ISC BIND named(8) DNS
// server as a caching only nameserver (as a localhost DNS resolver only).
//
// See /usr/share/doc/bind*/sample/ for example named configuration files.
//
// See the BIND Administrator's Reference Manual (ARM) for details about the
// configuration located in /usr/share/doc/bind-{version}/Bv9ARM.html

options {
  listen-on port 53 { 127.0.0.1; 7.1.8.8; };
  listen-on-v6 port 53 { ::1; };
  directory     "/var/named";
  dump-file     "/var/named/data/cache_dump.db";
  statistics-file "/var/named/data/named_stats.txt";
  memstatistics-file "/var/named/data/named_mem_stats.txt";
  allow-query     { localhost; 7.1.7.0/24; };
        allow-transfer{ localhost; 7.1.8.8; }; 
  /* 
   - If you are building an AUTHORITATIVE DNS server, do NOT enable recursion.
   - If you are building a RECURSIVE (caching) DNS server, you need to enable 
     recursion. 
   - If your recursive DNS server has a public IP address, you MUST enable access 
     control to limit queries to your legitimate users. Failing to do so will
     cause your server to become part of large scale DNS amplification 
     attacks. Implementing BCP38 within your network would greatly
     reduce such attack surface 
  */
  recursion yes;

  dnssec-enable yes;
  dnssec-validation yes;

  /* Path to ISC DLV key */
  bindkeys-file "/etc/named.iscdlv.key";

  managed-keys-directory "/var/named/dynamic";

  pid-file "/run/named/named.pid";
  session-keyfile "/run/named/session.key";
};

logging {
        channel default_debug {
                file "data/named.run";
                severity dynamic;
        };
};

zone "example.com" IN {
type master;
file "forward.example.com";
allow-update { none; };
};
zone "8.2.6.in-addr.arpa" IN {
type master;
file "reverse.example.com";
allow-update { none; };
};




include "/etc/named.rfc1912.zones";
include "/etc/named.root.key";

forward.example.com:

vi /var/named/forward.example.com

$TTL 86400
@   IN  SOA     ns1.example.com. root.example.com. (
        2011071001  ;Serial
        3600        ;Refresh
        1800        ;Retry
        604800      ;Expire
        86400       ;Minimum TTL
)
@       IN  NS          ns1.example.com.
@       IN  NS          ns2.example.com.
@       IN  A           7.8.8.1
@       IN  A           7.2.7.8

reverse.example.com:

vi /var/named/reverse.example.com
$TTL 86400
@   IN  SOA     ns1.example.com. root.example.com. (
        2011071001  ;Serial
        3600        ;Refresh
        1800        ;Retry
        604800      ;Expire
        86400       ;Minimum TTL
)
@       IN  NS          ns1.example.com.
@       IN  NS          ns2.example.com.
@       IN  PTR         example.com.
ns1     IN  A           7.1.8.8
ns2     IN  A           6.2.7.2

228     IN  PTR         ns1.example.com.
228     IN  PTR         ns2.example.com.

Eu tenho meu domínio registrado no godaddy. Eu atualizei o servidor de nomes ns1.example.com e ns2.example.com

Quando faço ping em qualquer cmd sem sshing, recebo este erro:

admin@admin-PC ~
$ nslookup example.com
*** UnKnown can't find example.com: Server failed
Server:  UnKnown
Address:  192.168.1.1

Quando faço ping no servidor, recebo isto:

admin@admin-PC ~
$ ping example.com
Ping request could not find host example.com. Please check the name and try again.

Eu criei dois nomes de host no godaddy com ns1 e ns2. e apontou para o endereço IP.

Tudo o que estou tentando é apontar o domínio para o vps. Eu sou um novato e não sei onde está o problema.

Como posso resolver isso?