DNS Records not found for a website

DNS Records not found for a website

I am running a dedicated server.
The server is running two sites. This morning one website is not working
and I found that there is a problem with the dns settings. I don't know
how it happened very suddenly.
The other website is working properly.
nslookup @domainname.com
Server: 8.8.8.8
Address: 8.8.8.8#53
** server can't find @domainname.com: NXDOMAIN
I checked online dns tools and they are reporting errors.
nslookup for another site is also not working
But dig for another site is working properly.
dig @domainname.com
dig: couldn't get address for 'domainname.com': not found
and ping is reporting
ping: unknown host domainname.com
dig SOA sitename.com
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.6 <<>> SOA sitename.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 25377
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 0
;; QUESTION SECTION:
;sitename.com. IN SOA
;; AUTHORITY SECTION:
co.in. 879 IN SOA a0.cctld.afilias-nst.info.
noc.afilias-nst.info. 2008728028 600 900 2592000 86400
;; Query time: 53 msec
;; SERVER: 8.8.8.8#53(8.8.8.8)
;; WHEN: Mon Sep 30 17:36:06 2013
;; MSG SIZE rcvd: 99
cat /etc/resolv.conf
nameserver 8.8.8.8
nameserver 8.8.4.4
I tried one online website for nslookup.
DNS server handling your query: localhost
DNS server's address: 127.0.0.1#53
** server can't find domain.co.in: NXDOMAIN
domain name : justforfun.co.in