You want more information on the outbound spam scanning or you have had emails stopped by the outbound spam scanning.
To provide continuity of service, Email Security scans all outbound emails and rejects the emails we identify as spam. To help you recognize these messages we send an SMTP permanent error response (5xx) to your message transfer agent (MTA). We suggest that you set your MTA to generate a non-delivery receipt (NDR) to inform the sender that we have blocked the email as spam.