I followed the multiserver setup How To
Everything was working great until I tried to mess with it.
I originally setup the mail server with the hostname "mail1". I decided I wanted to change the hostname to "mx1".
I changed the value in the mail server's /etc/hostname and /etc/mailname files. I also went through /etc/postfix/main.cf and changed the appropriate hostnames.
I went into the ISPConfig administration panel on the primary server and changed the hostname of the mail server under System->Servers.
I then changed my mind and reverted all the changes I had made. After reverting the changes, the mail server will still send and receive emails, but it doesn't appear that they primary server can control the mail server anymore.
For example, I tried creating a new email domain of "example.com". That domain was never created under /var/vmail of the mail server.
Please help. I tried finding some log files, but the ISPConfig log file on the primary server was empty.