ecards not getting to recipients

[Gephri]

Most recipients are not recieving the ecards I send.  When I send to myself at another of my domain emails they come through.
Wondering if HTML or images or something else is triggering some kind(s) of blockers on other peoples emails.  If so, is there a workd around on our end - such as a plain text alternative when blockers are detected in-route?

Thanks for the help.

[Sami]

first of all you should check your mail server
for example if your server does not have SPF record then all of your email to msn or hotmail or some other sites will marked as SPAM