a have a error when tyr send email

SqlConnection scon_forgott =
                           new SqlConnection(ConfigurationManager.ConnectionStrings["MyConnectionString"].ToString());



                       scon_forgott.Open();
                       DataTable dt = new DataTable();
                       SqlDataAdapter da = new SqlDataAdapter("select * from tbl_Users where Email='" + a.Text + "'",
                           scon_forgott);

                       da.Fill(dt);

                       if (dt.Rows.Count > 0)
                       {
                           string newpass = Guid.NewGuid().ToString();
                           string hashPass = FormsAuthentication.HashPasswordForStoringInConfigFile(newpass, "MD5");
                           Classes.Users clsUsers = new Classes.Users();
                           DataSet ds = clsUsers.SelectRow_User(dt.Rows[0]["UserName"].ToString());
                           DataRow drRow = ds.Tables["tbl_Users"].Rows[0];
                           clsUsers.updatePasswordNew(int.Parse(drRow["ID"].ToString()), hashPass);
                           MailMessage mail = new MailMessage();
                           mail.From = new MailAddress("email@mydomains.com");
                           mail.To.Add(new MailAddress(drRow["Email"].ToString()));
                           mail.Subject = "subjectttttt";
                           mail.Body ="booooooooodddddyyyyyyyyy";
                           mail.IsBodyHtml = true;
                           SmtpClient smtp = new SmtpClient("smpt.mydomains.com");
                           smtp.Credentials = new NetworkCredential("email@mydomains.com", "bIXSg1a8");
                           smtp.EnableSsl = false;
                           smtp.Send(mail);
                           Label lbl = LoginView1.FindControl("lblError") as Label;
                           lbl.ForeColor = Color.ForestGreen;
                           lbl.Text ="send new pass";
                       }
                       else
                       {
                           Label lbl = LoginView1.FindControl("lblError") as Label;
                           lbl.ForeColor = Color.Red;
                           lbl.Text = "user not found";
                       }