Error sending mail: "Relaying denied"

[Chris McAfee]

I have two mail servers configured, I get a "Relaying denied"
error when I try to send anything outside of either of these
domains now.  This was working fine for a long time, and started
failing for me yesterday.  I am using current 0.9.1 build on w2k.

Any idea what I need to change to fix this?  Please CC me on
any replies.

-Chris