This happens because our mail server treats the message you are sending as SPAM.
The message is considered to be SPAM if:
-'FROM' field is missing in the email message
-Neither 'FROM' nor 'TO' field contains an existing e-mail address on your mailserver.
-Your SMTP session is not being authenticated.
Please see Related Articles below.
Article ID: 180, Created: 4/23/2009 at 4:32 PM, Modified: 4/25/2009 at 12:14 PM