I am an IT professional working for 5 small tiny companies.

For a number of years I have installed and maintained various emai servers (exchange, Mdaemon)

Now I have two installations of Zimbra 8.0.4.

One of them is Working perfectly but other one started giving mi trouble.

It is an installation on Cent OS and domain is kreativaunlimited.com

Everything was working as it should until I did reply on a message from colegue and got message:
<user@domail.com>: Host or domain name not found. Name service
** *error for name=domail.com type=A: Host not found
In zimbra.log there is line:

Sep 6 13:03:49 mail postfix/smtp[23578]: 6E1902A1EA0: to=<user@domail.com>, relay=none, delay=0.11, delays=0.01/0.02/0.08/0, dsn=5.4.4, status=bounced (Host or domain name not found. Name service error for name=domail.com type=A: Host not found)
How is it possible that Zimbra forgot domain?!

Zimbra is on a public IP not behind firewall width port forward.

We are usig DNS of our ISP

cat /etc/resolv.conf

cat /etc/hosts localhost localhost.localdomain localhost4 localhost4.localdomain4
::1 localhost localhost.localdomain localhost6 localhost6.localdomain6 mail.kreativaunlimited.com mail

dig -t mx domail.com
; <<>> DiG 9.8.2rc1-RedHat-9.8.2-0.17.rc1.el6_4.5 <<>> -t mx domail.com
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 39058
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 3

;kreativaunlimited.com. IN MX

kreativaunlimited.com. 86400 IN MX 20 relay2.absolutok.com.
kreativaunlimited.com. 86400 IN MX 10 mail.domail.com.

kreativaunlimited.com. 86400 IN NS ns1.absolutok.com.
kreativaunlimited.com. 86400 IN NS ns2.absolutok.com.

mail.kreativaunlimited.com. 86400 IN A 91.143.***.**
ns1.absolutok.com. 86400 IN A
ns2.absolutok.com. 86400 IN A

;; Query time: 2 msec
;; WHEN: Sat Sep 7 12:16:13 2013
;; MSG SIZE rcvd: 177
After boot I get this error ant it was there from beginning

-bash: warning: setlocale: LC_CTYPE: cannot change locale (UTF-8): No such file or directory
In this post I changed my domain width domail.com

Dont understand it was working and now this happens width just few user ?! other users are fine