I'm totally new to ZIMBRA VM Appliance. I'm using VMPlayer to test the Z-Appliance.

We set up an evaluation instance of Zimbra Collaboration Suite Appliance on our local area network. We are running ZCA on our local network wehre we also have our corporate mail server. To avoid disrupting existing email operations, we have not changed our DNS MX record during the evaluation.

We created two local ZCA accounts but get the following error when account 1 sends an email to account 2:

May 2 15:23:12 asegvmail postfix/smtp[500]: 641AA360A4: to=<hmirsky3@asegvmail.aseg.com>, relay=none, delay=444, delays=444/0.03/0/0, dsn=4.4.1, status=deferred (connect to[]:10024: Connection refused)
May 2 15:23:12 asegvmail postfix/smtp[501]: CE5E43609E: to=<hmirsky2@asegvmail.aseg.com>, relay=none, delay=566, delays=566/0.03/0/0, dsn=4.4.1, status=deferred (connect to[]:10024: Connection refused)

Is there an additional configuration setting we may have missed? Any help would be appreciated.
The following has been accomplished:

Downloaded the appliance
Powered on the appliance
Created password for the virtual machine
Established the Zimbra Hostname
Completed the Admin Email address
Completed the Admin Password
Successfully Auto-fetch trial license
Accessed the Zimbra Administration Console
Completed static IP addresses
Verified the Zimbra server has a Host (A) record in DNS
Created two Email accounts