"550 5.7.512 Access denied, message must be RFC 5322 section 3.6.2 compliant and include a valid From address"

Email sent from on premise application servers and bound for office 365 recipients fails with the following error:

"550 5.7.512 Access denied, message must be RFC 5322 section 3.6.2 compliant and include a valid From address"

In the logs of your sending server you may see an SMTP conversation similar to:

220 BL2FFO11FD032.mail.protection.outlook.com Microsoft ESMTP MAIL Service ready at Mon, 28 Mar 2016 22:55:58 +0000

ehlo smtp.contoso.com

250-BL2FFO11FD032.mail.protection.outlook.com Hello [167.220.148.211] 250-SIZE 157286400

250-PIPELINING

250-DSN

250-ENHANCEDSTATUSCODES

250-STARTTLS

250-8BITMIME

250-BINARYMIME

250 CHUNKING

MAIL FROM: <>

250 2.1.0 Sender OK

RCPT TO: UserMailbox@contoso.com

250 2.1.5 Recipient OK

data

354 Start mail input; end with <CRLF>.<CRLF>

Hello World!

.

550 5.7.512 Access denied, message must be RFC 5322 section 3.6.2 compliant and include a valid From address

In the above sample SMTP communication you can see the "MAIL FROM" SMTP verb was submitted with a blank from address.

Resolution:

Application generating email must enter a valid from address.

A valid format would be as follows:

                 From: “No Reply” <NoReply@contoso.com>

                -or-

                From: NoReply @contoso.com

 

Blank from fields or anything formatted differently from above could be rejected.