Generating email in a asp.net project

[twiggy2k]

I've written this code:

Dim mailObj As New MailMessage

mailObj.From = Session(Constant_Table.user_email_session)
mailObj.To = Constant_Table.MAILORDER_from
mailObj.Subject = Constant_Table.MAILORDER_subject
mailObj.BodyFormat = MailFormat.Html
mailObj.Body = Invoice_details

SmtpMail.SmtpServer = "mail.catalyst2.com"
SmtpMail.Send(mailObj)

this is using mail.catalyst2.com mail server.... any ideas why it's not working?

[Jacob]

The From address must be an address where the mail account is on our mail server.

Regards,

Jacob