following the link from the second response generates this information:
This error indicates one of the following:
The sending machine or network has a security problem associated with it, which resulted in the sending of unsolicited bulk mail to our subscribers or role accounts.
The sending machine or network is actively attacking our mail servers (mailbomb, DoS attack, etc).
The sending machine or network is located within a dynamically assigned IP address pool, and the ISP owning that pool has a stated "no server" policy.
The sending machine or network is not in compliance with Road Runner's posted Inbound Sending Policies
Does anyone know if the F9 mail server is indeed blacklisted, or are there any headers in the email I can redefine to allow the email to be sent correctly?