Strictly speaking 5.7.1 is X.7.1 Delivery not authorized, message refused The sender is not authorized to send to the destination. This can be the result of per-host or per-recipient filtering. This memo does not discuss the merits of any such filtering, but provides a mechanism to report such. This is useful only as a permanent error. In other words, it looks like you've been filtered, either at the host level or at the user level. Nathan