Problem After Changing Hostname

In an attempt to have good DNS records, I changed the Hostname on MY ISPConfig server And Postfix from server1.example.com to mail.cass.lib.mi.us. I am running the ISPConfig Virtual Appliance. Now when I try to send mail to e-mails @ cass .lib.mi.us I get this error:

<[email protected]> (expanded from

<[email protected]>): mail for server1.example.com loops back to
myself

What have I missed?

Thanks again for all of your help.

 

I changed the hostname in several places as described here.

Now the error I get is this:<[email protected]> (expanded from <[email protected]>):
[server1.example.com]: Name or service not known

 

can anyone help me?

 

What's in /etc/postfix/main.cf? What's the output of

Code:

hostname

and

Code:

hostname -f

?