Thanks for reading. I have PostFix running on "The Perfect Etch Setup". At first, it wasn't authenticating. I think that was because I didn't have maildir checked in ISPConfig. But now, it is authenticating, and receiving mail from several of my email accounts, but it is not sending mail. I get a message saying: ================= Your message did not reach some or all of the intended recipients. Subject: Test Sent: 3/23/2008 8:51 PM The following recipient(s) could not be reached: 'email@example.com' on 3/23/2008 8:51 PM 554 5.7.1 < HYPERLINK "mailto:firstname.lastname@example.org" email@example.com>: Relay access denied ================= A little more history: There are 2 domains explained herein. One is a sub-domain which is the name of the server itself. The other is a domain hosted on this server. The email/domain hosted on the server doesn't send mail. Just receives mail. This server, "The Perfect Etch Setup" running Postfix is a actually named as a sub-domain of another domain ... I use Outlook to authenticate (Please don't flame me about using Microsoft), so POP and SMTP settings are both set to the sub-domain name. Is this a sub-domain name issue or does that matter? I tried going into DNS management for the domain and changing the MX record to just the IP address thinking that was the issue, and DNS doesn't like just the IP address of my mail server. Anyone have any ideas? Thanks.