Hi to Everyone... please I need some help.

I have problems with my ZCS 5.18.x

I can Recive e-mail but I can't make a reply o create a new one for that direcction.

I have the error in the tittle.

Jun 7 18:19:26 correo postfix/smtp[24036]: BEB8B99000B: to=<monicah@gtdinternet.com>, relay=127.0.0.1[127.0.0.1]:10024, delay=0.52, delays=0.05/0/0/0.47, dsn=2.0.0, status=sent (250 2.0.0 Ok: queued as 45A51990027)
Jun 7 18:19:26 correo postfix/smtp[28331]: 45A51990027: to=<monicah@gtdinternet.com>, relay=none, delay=0.03, delays=0.01/0.01/0.01/0, dsn=5.4.4, status=bounced (unable to look up host gtdinternet.com: Name or service not known)


Some usefull info:

[root@correo ~]# dig gtdinternet.com mx

; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_4.2 <<>> gtdinternet.com mx
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 9028
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 3

;; QUESTION SECTION:
;gtdinternet.com. IN MX

;; ANSWER SECTION:
gtdinternet.com. 300 IN MX 10 zs.gtdinternet.com.

;; AUTHORITY SECTION:
gtdinternet.com. 128 IN NS ns.gtdinternet.com.
gtdinternet.com. 128 IN NS ns2.gtdinternet.com.

;; ADDITIONAL SECTION:
zs.gtdinternet.com. 128 IN A 201.238.246.120
ns.gtdinternet.com. 207 IN A 200.75.0.2
ns2.gtdinternet.com. 299 IN A 200.75.0.3

;; Query time: 6 msec
;; SERVER: 200.75.0.5#53(200.75.0.5)
;; WHEN: Mon Jun 7 18:50:37 2010
;; MSG SIZE rcvd: 135

[root@correo ~]# dig gtdinternet.com any

; <<>> DiG 9.3.6-P1-RedHat-9.3.6-4.P1.el5_4.2 <<>> gtdinternet.com any
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 22352
;; flags: qr rd ra; QUERY: 1, ANSWER: 3, AUTHORITY: 2, ADDITIONAL: 3

;; QUESTION SECTION:
;gtdinternet.com. IN ANY

;; ANSWER SECTION:
gtdinternet.com. 260 IN MX 10 zs.gtdinternet.com.
gtdinternet.com. 88 IN NS ns2.gtdinternet.com.
gtdinternet.com. 88 IN NS ns.gtdinternet.com.

;; AUTHORITY SECTION:
gtdinternet.com. 88 IN NS ns2.gtdinternet.com.
gtdinternet.com. 88 IN NS ns.gtdinternet.com.

;; ADDITIONAL SECTION:
zs.gtdinternet.com. 88 IN A 201.238.246.120
ns.gtdinternet.com. 167 IN A 200.75.0.2
ns2.gtdinternet.com. 259 IN A 200.75.0.3

;; Query time: 6 msec
;; SERVER: 200.75.0.5#53(200.75.0.5)
;; WHEN: Mon Jun 7 18:51:17 2010
;; MSG SIZE rcvd: 163

[zimbra@correo ~]$ host `hostname`
correo.bee.cl has address 200.55.208.245
[zimbra@correo ~]$ host -a bee.cl
Trying "bee.cl"
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 65280
;; flags: qr rd ra; QUERY: 1, ANSWER: 6, AUTHORITY: 3, ADDITIONAL: 5

;; QUESTION SECTION:
;bee.cl. IN ANY

;; ANSWER SECTION:
bee.cl. 55089 IN MX 10 correo.bee.cl.
bee.cl. 55089 IN MX 20 mail.bee.cl.
bee.cl. 55089 IN A 200.55.208.245
bee.cl. 78873 IN NS secundario.nic.cl.
bee.cl. 78873 IN NS dns.bee.cl.
bee.cl. 78873 IN NS ns.gtdinternet.com.

;; AUTHORITY SECTION:
bee.cl. 78873 IN NS secundario.nic.cl.
bee.cl. 78873 IN NS dns.bee.cl.
bee.cl. 78873 IN NS ns.gtdinternet.com.

;; ADDITIONAL SECTION:
correo.bee.cl. 269 IN A 200.55.208.245
mail.bee.cl. 55089 IN A 200.55.208.245
secundario.nic.cl. 19392 IN A 200.1.123.7
ns.gtdinternet.com. 238 IN A 200.75.0.2
dns.bee.cl. 72999 IN A 200.55.208.245

Received 285 bytes from 200.75.0.5#53 in 7 ms
[zimbra@correo ~]$
[zimbra@correo ~]$ zmcontrol -v && zmcontrol status


Release 5.0.18_GA_3011.RHEL5_20090707164432 CentOS5 FOSS edition

Host correo.bee.cl
antispam Running
antivirus Running
ldap Running
logger Running
mailbox Running
mta Running
snmp Running
spell Running
stats Running
[zimbra@correo ~]$

What can I do ???

Please... HEELP!