SDM email is configured to use SMTP without authentication. A Manual Notification to one contact reaches an inbox if the contact has one email address, which happens to belong to a group ('SUPPORT@customer.com'), but not if the contact's email address is changed to their individual email ('DoeJohnP@customer.com'). Nothing appears in the stdlog, and the mail_queue, mail_unknown and mail_undeliverable folders are empty. So it appears that SDM correctly passes the email on to SMTP in both cases, as you'd expect. I'm at a loss to understand why SDM would behave differently for different email addresses, so my suspicion is there is something odd about the way their SMTP traffic is being handled. My first reaction was to Telnet to port 25 and run an SMTP session by hand to verify that SMTP is behaving as expected (or not), but the Telnet client is not installed on the SDM server and the customer is reluctant to let me install it. What can I do to enable some in depth logging from SDM's email handling? Regards, James