here is some more info,
-- 235 Authentication succeeded
--> MAIL FROM:<bam@thegrinder.ws>
--> RCPT TO:<bam@thegrinder.ws>
--> DATA
<-- 250 OK
<-- 250 Accepted
<-- 354 Enter message, ending with "." on a line by itself
--> Date: Mon, 17 Apr 2006 09:36:21 -0700 (PDT)
--> From: bam <zaurus@thegrinder.ws>
--> X-X-Sender: zaurus@localhost.localdomain
--> To: bam@thegrinder.ws
--> Subject: testing mail
--> Message-ID: <Pine.LNX.4.64.0604170935540.1623@localhost.localdomain>
--> MIME-Version: 1.0
--> Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
-->
--> test mail
--> .
<-- 550 Administrative prohibition
msmtp: the server did not accept the mail
msmtp: server message: 550 Administrative prohibition
msmtp: could not send mail (account default from /home/zaurus/.msmtprc)
FAILURE
any more suggestions?