Blank HTML messages sent to Yahoo! users (and even Gmail or Hotmail users)

[eluser]Aqua193[/eluser]
Hi -

Our site is running into an issue with mailing lists. We send e-mails to folks who sign up for our newsletter; first, a welcome message, then an HTML newsletter with graphics. If they want to unsubscribe, we send them a confirmation message.

Our dev team wrote the code on an Apache box running Windows. Everything worked fine - all the e-mails are successfully sent to Yahoo!, GMail, and Hotmail users and are visible in their HTML beauty.

Our production box is running IIS/Windows, however. For some reason, all messages sent to Yahoo! users are blank (subject line in tact, however). Some e-mails make it to the Gmail and Hotmail users - except the unsubscription confirmation.

The weird thing is that the unsubscription and registration files are exactly the same - just some free text in an HTML document that we mail out to users. Why one would work, while the other one doesn't, strikes me as odd.

Even more so, why everything works on Apache but breaks on IIS is also weird.

We saw the posts at:

http://ellislab.com/forums/viewthread/88008/
http://ellislab.com/forums/viewthread/49097/
http://ellislab.com/forums/viewthread/55149/

but no luck so far. Can someone help us?

[eluser]Derek Jones[/eluser]
What version of CI are you using, and have you hacked, modified, or extended the Email library?

[eluser]Aqua193[/eluser]
Hi Derek,

We are using V 1.O (from the header of the Email.php file). And no, I don't believe we have done anything to the library.

[eluser]Aqua193[/eluser]
One more thing - even though the e-mails are blank in Yahoo!, when I look at the full headers, the content seems to be showing up:

From xxxxxxx Mon Dec 1 10:34:09 2008
Return-Path: <[email protected]>
Authentication-Results: mta217.mail.mud.yahoo.com from=sailawaywithme.com; domainkeys=neutral (no sig)
; from=sailawaywithme.com; dkim=neutral (no sig)
Received: from 216.82.92.76 (EHLO smtp.appliedi.net) (216.82.92.76)
by mta217.mail.mud.yahoo.com with SMTP; Mon, 01 Dec 2008 10:32:42 -0800
Received: from web10.appliedi.net [216.82.70.70] by smtp.appliedi.net with SMTP;
Mon, 1 Dec 2008 13:41:46 -0500
Subject: can
To: xxxxxxxxxx
User-Agent: smtp.appliedi.net
Date: Mon, 1 Dec 2008 13:34:09 -0500
From: &lt;[email protected]&gt;
Return-Path: &lt;[email protected]&gt;
Reply-To: "[email protected]" &lt;[email protected]&gt;
Message-ID: <[email protected]>
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="B_ALT_49342e21775c2"
This is a multi-part message in MIME format.
Your email application may not support this format.
--B_ALT_49342e21775c2
Content-Type: text/plain; charset=iso-8859-1
Content-Transfer-Encoding: 8bit
...
Sponsored link
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ready. Guests will delight at an old-fashioned turntable and mustache-shaped
key holder. Where to find such palatial gear? Red Hot Shop at Target.com, of
course.
...
...
--B_ALT_49342e21775c2
Content-Type: text/html; charset=iso-8859-1
Content-Transfer-Encoding: quoted-printable
Content-Length: 13676

[eluser]Derek Jones[/eluser]
I think you're confusing the copyright statement with the CI version. Do you know what version of CI you are running? I think you'll be fine if you just update CodeIgniter.

[eluser]Aqua193[/eluser]
Hi Derek, I checked -- we used the Email.php file from Codeigniter v.1.7.0, which I believe is the latest?

[eluser]Derek Jones[/eluser]
Have you tried modifying the line break and line feeds? Or routing the email through a different SMTP server? Could be something as simple as processing occurring on one server after accepting the email from CI and not the other.