For here, the exact message is "550 , Recipient unknown". In that particular exemple, the email of the sender was m_estone@compuserve.com which is ok and the recipient email was Mike.Harris.Stone@gmail.com which is also ok. As I said, if I recall that record, it'll work ok on the 2nd try. This is usually working 95% of the time. It used to be 100% of the time before I upgraded to a newer version. I just don't know why this is not working sometimes.
