Why is my email being rejected? - email

Question

I am having problems sending an email from one email address to another on my domain. I am using a shared server. I use weather software which automatically constructs and sends the email message. I have omitted the host, domain and IP info and replaced them like so: host= example.co.uk, domain = mydomain.co.uk .
The situation is I run a mail group using email address (weatherinfo#) and some users in the group set auto-responders. Therefore to prevent these from going to the whole group the email is sent from a different address (reports#) to weatherinfo# with the reports# address receiving the auto-responder messages.
I am getting the following message from the mail delivery system when trying to send the email to weatherinfo# from report#:
This is the mail system at host mailauth.example.co.uk.
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
For further assistance, please send mail to postmaster.
If you do so, please include this problem report. You can
delete your own text from the attached returned message.
The mail system
<weatherinfo#mydomain.co.uk>: host 127.0.0.1[127.0.0.1] said: 554 5.6.0
Reject, id=02474-18 - BAD HEADER (in reply to end of DATA command).
The error log accompanying the email shows:
Reporting-MTA: dns; mailauth.example.co.uk
X-Postfix-Queue-ID: 88002C306D
X-Postfix-Sender: rfc822; reports#mydomain.co.uk
Arrival-Date: Fri, 2 May 2014 22:00:43 +0100 (BST)
Final-Recipient: rfc822; weatherinfo#mydomain.co.uk
Original-Recipient: rfc822;weatherinfo#mydomain.co.uk
Action: failed
Status: 5.6.0
Remote-MTA: dns; 127.0.0.1
Diagnostic-Code: smtp; 554 5.6.0 Reject, id=02474-18 - BAD HEADER
The header from the original message is:
Return-Path: <reports#mydomain.co.uk>
Received: from LAPTOP (helium.example.co.uk [IP Address])
by mailauth.example.co.uk (Postfix) with ESMTPA id 88002C306D
for <weatherinfo#mydomain.co.uk>; Fri, 2 May 2014 22:00:43 +0100 (BST)
To: weatherinfo#mydomain.co.uk
From: reports#mydomain.co.uk
Subject: WEATHER REPORT
Reply-To: reports#mydomain.co.uk
Date: Fri, 02 May 2014 23:00:56 +0100
Message-Id: <43786804l.820319781l1635676l1l#mydomain.co.uk>
Message-ID: <2014.05.02.17001.wd#mail.mydomain.co.uk>
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Type: text/plain; charset="us-ascii"
Why is this message being rejected?
Is this being caused by my software or the server?
If it is the software what does the developer need do to fix it?
If it is the server what should I ask my host to do to overcome this problem?

Answer 1

The server says, your header is wrong, so I'd search the problem within your software.
If it isn't just a missing whitespace in your post, the header field "Recieved" isn't folded as specified in RFC 2822: 2.3.3 Long Header Fields causing two invalid headers starting with "by" and "for". Correct would be:
Received: from LAPTOP (helium.example.co.uk [IP Address])
by mailauth.example.co.uk (Postfix) with ESMTPA id 88002C306D
for <weatherinfo#mydomain.co.uk>; Fri, 2 May 2014 22:00:43 +0100 (BST)
Also I see that there are two Message-id headerfields. I do not know whether this is allowed or not.
I would always do tests with telnet (or putty/raw) in such a case and try with several heder fields skipped or modified so you can break it down to the header field your mail server is complaining about.