I received this message below within SendGrid that was being sent to Gmail. However this has always worked, and of course I am have a FROM email address included. Is this something else or a bug?

550 5.7.1 [ 11] Our system has detected that this message is not RFC 5322 compliant: 'From' header is missing. To reduce the amount of spam sent to Gmail, this message has been blocked. Please visit https://support.google.com/mail/?p=RfcMessageNonCompliant and review RFC 5322 specifications for more information. k7si5926825iok.8 - gsmtp
  • It would help if you could post the headers from a message that failed its delivery. – Jenny D Mar 29 '17 at 12:24

I had this issue with PHP sending via SendGrid to Gmail. It seems to be solved by changing the From header to have the email address in between < and >.


From: someone@example.com


From: <someone@example.com>
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Looks like SendGrid are having issues with this today.

From their support team:


Thanks for reaching out. Our team is aware of an issue that is causing the return-path to get added to the from address or removing the from address. This can also cause the return-path to be displayed as the subject line in some cases or return an empty subject line. The engineers are currently determining the scope of this error as this has just been seen and looking into resolving it. I will keep this ticket open and let you know when I have an update.

Thank you for your understanding,

Hopefully they will sort this out soon.

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