Symptom:

I receive "All servers failed to receive the message " when using JMAIL on my site to send form info via email

Resolution:

This usually means your code isn't using SMTP-auth to authenticate when connecting to the mail server OR if you are using SMTP-auth, it means you're supplying an incorrect username/pw combination.  See the sample code in the following article for using jmail... it shows how to properly implement smtp-auth.

http://knowledge.3essentials.com/web-hosting/article/27/Sending-mail-from-a-web-page-using-ASP-and-JMail.html