==== Provide required information to help troubleshoot and get quick answer ====
- iRedMail version: latest
- Linux/BSD distribution name and version: Centos 5.6
- Any related log? Log is helpful for troubleshooting.
====

I receive some bounced mail reported error while receiving "Server Greeting" message:

<----omssis---@libero.it>: delivery temporarily suspended: conversation with
   liberomx3.libero.it[212.52.84.180] timed out while receiving the initial
   server greeting
Reporting-MTA: dns; [myserver]
X-Postfix-Queue-ID: 7DB042BE035B
X-Postfix-Sender: rfc822; newsletter@sender
Arrival-Date: Thu,  5 Apr 2012 12:51:33 +0200 (CEST)

Mail log report:

Apr 10 12:10:48 posta postfix/smtp[8155]: 9A4882BE02BA: conversation with liberomx1.libero.it[212.52.84.177] timed out while receiving the initial server greeting

...

What is the problem?

Thanks in advance...