Centos – Cannot find solution to “One or more of your nameservers did not return any of your NS records.” on intoDNS site

I have set up DNS on my Linux Centos server and when I test on this site I get the following errors:

WARNING: One or more of your nameservers did not return any of your NS
records.

ERROR: One or more of your nameservers did not respond:

The ones that did not respond are:

49.50.77.196 49.50.77.200

Researching across the web/Stack Exchange, I understand it appears to be my DNS A records that aren't correctly set up but for the life of me and 2 days trial/error I cannot find what is wrong:

dig indulgense.com

; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.30.rc1.el6_6.1 <<>> indulgense.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 39107
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 0, ADDITIONAL: 0

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

;; Query time: 5005 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Feb  2 20:28:42 2015
;; MSG SIZE  rcvd: 32

dig @49.50.77.196 indulgense.com. soa

; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.30.rc1.el6_6.1 <<>> @49.50.77.196 indulgense.com. soa
; (1 server found)
;; global options: +cmd
;; connection timed out; no servers could be reached

My /var/named/indulgense.com.zone zone file is:

$TTL    7200
@       IN      SOA     indulgense.com. contact.indulgense.com. (
                        2015020211      ; Serial        yyyymmddss (ss: sequence serial)
                        7200            ; Refresh       3h
                        3600            ; Retry         1h
                        240800          ; Expire
                        7200            ; Minimum       3h
)

@       IN NS           ns1.indulgense.com.
@       IN NS           ns2.indulgense.com.
ns1     IN A            49.50.77.196
ns2     IN A            49.50.77.200
ftp     IN CNAME        indulgense.com.
www     IN CNAME        indulgense.com.
*       IN CNAME        indulgense.com.
@       IN MX 10        indulgense.com.

indulgense.com. IN A 49.50.77.196
indulgense.com. IN TXT "v=spf1 ip4: 49.50.77.196/29 -all"

bindera.indulgense.com. IN A 49.50.77.200
bindera.indulgense.com. IN TXT "v=spf1 ip4: 49.50.77.200/29 -all"

This is my /etc/named.conf file:

//
// 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.
//

options {
        listen-on port 53 { 127.0.0.1; };
        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     { any; };
        recursion no;

        dnssec-enable yes;
        dnssec-validation yes;
        dnssec-lookaside auto;

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

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

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

zone "." IN {
        type hint;
        file "named.ca";
};

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


zone "indulgense.com" IN {
                type master;
                file "/var/named/indulgense.com.zone";
                allow-update { none; };
        };

Any help would be appreciated along with any other info needed…