A new, weeks old, installation of Zimbra Release 6.0.1_GA_1816.RHEL5_20090911181524 CentOS5 FOSS edition.
Suddenly all my email get queued and maillog just displays:

Nov 30 08:42:27 correo postfix/smtp[7306]: 774E6B0DD40: conversation with gmail-smtp-in.l.google.com[] timed out while receiving the initial server greeting

In this case, the example points to gmail, but it is happenning with ALL the domains we try to send email to.

A reboot of the server does not fix the issue, we use OpenDNS as our Zimbra DNS, we have not installed patches or upgrades to the Centos5 we are using.

The only yhing i see is that the "stats" service keeps dying for no reason.

thanks for your comments.