Sending Email from Server

Good Morning.
I have an asp app that works great on my development laptop, and on my windows 2003 server.
All except email. I can send emil form my laptop using the following code (button click event of a testmail.aspx page)

protected void Button1_Click(object sender, EventArgs e)
    {
        try
        {
            string tempsubject = TextBox1.Text;
            //send the staff assigned to that dept an email and a link to the staff/profile page ***change it here***
            MailMessage message = new MailMessage("SAITS@stuaf.umass.edu", "dharper@stuaf.umass.edu",  tempsubject, "Test body");
       &nbs ...