[techtalk] exim sending problems

[James]

(Sending this from non subscribed account for reasons obvious below)   Someone *cough* had to format and reinstall everything on their Debian router/firewall/server.  So after a reinstall of everything, we get this error when I try to send email out through my exim SMTP server.   The message could not be sent because one of the recipients was rejected by the server. The rejected e-mail address was '[EMAIL PROTECTED]'. Subject 'Some subject', Account: 'mail.kathweb.net', Server: 'mail.kathweb.net', Protocol: SMTP, Server Response: '550 relaying to <[EMAIL PROTECTED]> prohibited by administrator', Port: 25, Secure(SSL): No, Server Error: 550, Error Number: 0x800CCC79   (Receivers email changed for the sake of some sense of privacy :))   Any idea of what causes this?  Been over the exim.conf file and the FAQ and can't figure it out yet.  I know it is something obvious and I know it can work since it worked before.   - James