SendMail: missing a valid Message-ID header

General
1

Hello, I’ve been sending emails from my Xojo application for years, using Socket.SendMail. But now, I get the following response on several addresses:

<tony.candato@easycompany.fr>: host aspmx.l.google.com[192.178.223.26] said: 550-5.7.1 [197.158.77.51] Messages missing a valid Message-ID header are not 550-5.7.1 accepted. For more information, go to 550-5.7.1 https://support.google.com/mail/?p=RfcMessageNonCompliant and review 550 5.7.1 RFC 5322 specifications. ffacd0b85a97d-45493008ffbsi2614793f8f.335 - gsmtp (in reply to end of DATA command)

My provider (and the AI) confirm that this is a problem originating from the email creation tool, specifically my Xojo program (8sens).

How can I avoid these problems?

Tanks

2

Haven’t you add a header for the message-id?

mail.Headers.AddHeader("Message-ID", "blabla")

3

I added the following three: “X-Mailer”, “Content-Type” and “X-8sensID"

4

Neither X-Mailer nor Content-Type or X-8sensID are a Message-ID.

2 Likes
5

Adding a Message-ID header makes sending emails much better.
Thanks Beatrix !