ارسال ایمیل

public void SendMail(string Subject, string To, string Body)

{
SmtpClient smtp = new SmtpClient();
MailMessage mailMessage = new MailMessage();
//فرستنده
mailMessage.From = new MailAddress(TextBox14.Text);
//گیرنده 
mailMessage.To.Add("[email protected]");
//عنوان
mailMessage.Subject = TextBox13.Text;
//بدنه ایمیل
mailMessage.Body = TextBox15.Text;
mailMessage.IsBodyHtml = false;
// useame & password 
NetworkCredential credential = new NetworkCredential(" tavasolhamid ", " hamidtavasol ");
smtp.UseDefaultCredentials = false;
smtp.Credentials = credential;
smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
//port & host
smtp.Port = 587;
smtp.EnableSsl = true;
smtp.Host = "smtp.gmail.com";
smtp.Send(mailMessage);
}
protected void Button8_Click(object sender, EventArgs e)
{
string mail = "mailMessage.From:{0} mailMessage.To.Add:{1} mailMessage.Subject:{2} mailMessage.Body:{3}";
mail = string.Format(TextBox14.Text, "mailMessage.To.Add", TextBox13.Text, TextBox15.Text);
SendMail("mailMessage.To.Add", "mailMessage.Subject", "mailMessage.Body");

}

smtp.Send(mailMessage);

failure sending mail