I'm trying to create a script where when a user clicks on a button, it will send them an email.. The code compiles, however, when I click on the button it says "Failure sending mail" Here is the code:

private void button1_Click(object sender, EventArgs e)
            string mailServerName = "smtphost";
            string from = "example@example.com";
            string to = "example@example.com";
            string subject = "mailings";
            string body = "this is a test, this is a test";

            MailMessage message = new MailMessage(from, to, subject, body);

            SmtpClient mailClient = new SmtpClient(mailServerName)
            mailClient.UseDefaultCredentials = true;

            // Send delivers the message to the mail server


Please help, thanks