Gmail email rejected

Philip Tulett philip.tulett at
Wed Nov 2 09:15:22 UTC 2022

Hi Kim,

It sounds like a few things changed at/around the same time, so I would try
to reduce these to find the root cause of the issue.

First, can your system send an email successfully to the name at but
with a pdf attachment ?

Can you include another email address (say your address) as a BCC to the
email being sent to name at ?
You will them be able to view the raw message including all headers in your
copy of the message.

One of my systems send emails with pdf attachments and it will send to gmail
addresses without issue. The messages are being sent from an Microsoft365
mailbox using the latest Studio 10.2, I do not set a messageID header
manually, Office365 takes care of that for me.

Kind regards

-----Original Message-----
From: omnisdev-en <omnisdev-en-bounces at> On Behalf Of
kim at
Sent: 02 November 2022 08:53
To: OmnisDev List - English <omnisdev-en at>
Subject: Gmail email rejected


I have client that that has started sending the pdf files as an attachment
to an email by smtp directly from the program.

They have all gone through except for gmail address.  Eg name at
<mailto:name at>  

The following message was:

This Message was undeliverable due to the following reason:

Your message was not delivered because the destination computer refused to
accept it (the error message is reproduced below). This type of error is
usually due to a mis-configured account or mail delivery system on the
destination computer; however, it could be caused by your message since some
mail systems refuse messages with invalid header information, or if they are
too large.

Your message was rejected by for the following

5.7.1 [] Messages missing a valid messageId header are not
5.7.1 accepted. b12-20020a170903228c00b00186ff4b98a1si15640246plh.208 -

The following recipients did not receive this message:

name at <mailto:name at> 


Internet provider is Telstra :    works for all
other emails

The business just recently changed their email address to a business email
with a new company.  I was wondering whether this may be a problem and they
may require some other authorisation. 


What settings do you require to allow emails to go by smtp too gmail


Any ideas would be greatly appreciated



Kim Martel

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