The only thing changed on the server was the external IP address as we moved to a different internet provider. Server is live on internet and not behind a firewall. The DNS changes were made at our providers DNS server and the DNS lookups reflect the new correct address.
[zimbra@energon log]$ zmcontrol status
zmmtaconfig is running.
mailboxd is not running.
zmmailboxdctl is not running
[zimbra@energon log]$ zmcontrol -v
Release 5.0.26_GA_3365.RHEL5_64_20101215140819 RHEL5_64 NETWORK edition
I have generated a self signed SSL certificate incase the IP address change caused a problem and also repaired the Zimbra permissions