Maybe a DNS issue. Please post the following
Code:
cat /etc/hosts
cat /etc/resolv.conf
dig yourdomain.com MX
dig yourdomain.com NS
host `hostname` <- note backticks and not double quotes
are you sat behind a firewall ? have you disable SELinux ?
Also,
http://www.zimbra.com/forums/announc...r-profile.html so we know which O/S etc.