My website sends out html emails but most of my recipients are receiving them as HTML marked up source pages instead of the nice table layouts.
The problem doesn't appear to be an email client issue since the emails display properly in web mail clients like gmail, yahoo, hotmail etc... They also display properly when viewed through outlook or thunderbird that are connected to gmail, yahoo, hotmail etc...
However, I have one domain name that I registered with a shared hosting provider called 1and1.com. I tried viewing my emails through their webmail client, thunderbird and outlook, but in all three cases, only the html mark up showed up.
Also, I assume most of my recipients use MS Outlook with MS Exchange Server because they are business/finance people. Unfortunately, I don't know how to get an email that's managed by an MS Exchange Server.
I made sure I'm sending my emails with the following headers:
MIME-Version: 1.0
Content-type: text/html; charset=iso-8859-1
Does anyone know what might be wrong? can anyone recommend a solution?
Additional Info It appears my email on shared hosting can receive html emails from sites like youtube, but not from my php mail() function. So am I doing something wrong such as not sending enough header information? maybe i'm not encoding something properly?