That doesn't conform to RFC 2821: 4.2.5 Reply Codes After DATA and the Subsequent <CRLF>.<CRLF> When an SMTP server returns a positive completion status

That doesn't conform to RFC 2821: 4.2.5 Reply Codes After DATA and the Subsequent <CRLF>.<CRLF> When an SMTP server returns a positive completion status (2yz code) after the DATA command is completed with <CRLF>.<CRLF>, it accepts responsibility for: - delivering the message (if the recipient mailbox exists), or - if attempts to deliver the message fail due to transient conditions, retrying delivery some reasonable number of times at intervals as specified in section 4.5.4. - if attempts to deliver the message fail due to permanent conditions, or if repeated attempts to deliver the message fail due to transient conditions, returning appropriate notification to the sender of the original message (using the address in the SMTP MAIL command). If it's spam, the email should be rejected while the SMTP connection is still established with an error code (4XX or 5XX). If the email was accepted for delivery, there are really only two options: deliver the email or bounce it back to the sender.