On 7/13/22 12:31 AM, Philip Paeps via mailop wrote:
In the past couple of days, I'm seeing an uptick in rejects from Gmail
as follows:
>Our system has detected that this message is not RFC 5322 compliant.
Similar to this, some our customers complained that messages sent to
Gmail have been bouncing since June 15 with:
550-5.7.1 [ip_redacted] Messages missing a valid messageId header are not
550 5.7.1 accepted.
The messages indeed do not have a "Message-ID" header; they're being
sent from the Windows 10 built-in "Mail" app.
I'm a little surprised that the Windows Mail app doesn't include a
Message-ID, but
<https://datatracker.ietf.org/doc/html/rfc5322#section-3.6.4> says it's
only a SHOULD, not a MUST.
Anyone else seeing the same thing? Now I'm in the position of having to
either start adding missing Message-ID headers, which people online
recommend against because it potentially breaks DKIM, or telling people
Windows Mail no longer works to send to Gmail. Neither is ideal.
--
Robert L Mathews
_______________________________________________
mailop mailing list
mailop@mailop.org
https://list.mailop.org/listinfo/mailop
