Sysadmin Pro and Email Setup

I just download and installed the lastest Distro and FREEPBX. 13.
I purchased sysadmin pro, and wanted to use the existing email server to send out my emails. However, I do not change any setting under use existing and the emails are not being sent. Does anyone know the proper configuration to use the internal em,ail server. i am not worried about the spam, as I can set to let it thru clear?

I am looking to understand what to use in these blanks as its required for gmail and office 365

The myhostname parameter specifies the internet hostname (also known as the Reverse DNS) of this mail system. The default is to use the Reverse DNS lookup name from gethostname().

The mydomain parameter specifies the local internet domain name. The default is to use $myhostname minus the first component.

The mydomain parameter specifies the local internet domain name. The default is to use $myhostname minus the first component.

Just very confusing and difficult to track where an error is in sending information.

Post the maillog, you can find it in /var/log/maillog.

I setup a new gmail and used pro version all are coming thru. Thanks