Problems with Outlook
We are sending out a newsletter that is compiled using PHP scripts, and we send this newsletter to thousands of users every month.
We have received feedback from subscribers who use Outlook that the newsletter is not displaying correctly: instead of being HTML formatted, they see the HTML code itself.
I already know about the Outlook 2007 issue about using the Word 2007 rendering engine instead of the IE rendering engine, but our problem cannot deal with that, because no HTML rendering is happening at all. The subscribers simply see the HTML code in plain-text view.
Considering it is happening with a lot of people, and they are all using Outlook, we figure Outlook probably needs some type of extra flag or header sent with the email to indicate that the email should be HTML formatted, but I would like more information on this. Does anyone know what the problem could be? Is there any header that is specific to Outlook that we need to include in the email message to tell Outlook to display it as HTML content and not plain text?
The emails are being displayed in all other mail programs that we know of (Thunderbird, Mac OS X Mail, etc.)