SMTP 554 Client policy violation - Reverse DNS Failed

The SMTP 554 error can happen when a server rejects email sent from a computer with a dynamic IP address, such as most computers that are connected to the Internet via DSL or cable modem. The best solution is to resend email from a Yahoo, Hotmail, or GMail account notifying the recipient of the problem.

Example of Error Response:
Final-Recipient: rfc822; <***@***.com> Action: failed Status: 5.1.0 MAIL FROM: <***@***.com> 554 REPLY: 554_Client_policy_violation_-_can't_deliver_mail_from_your_location_without_authentication_(reverse_DNS_failed_on_63.240.77.85). Diagnostic-Code: smtp; Permanent Failure: Other address status Last-Attempt-Date: Wed, 16 Aug 2006 18:22:58 -0000