Forgot password get by mail using SMTP

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Net.Mail;
using System.Net;

public partial class ForgetPassword : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        string username = "";
        string password = "";
        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["conn"].ConnectionString);
        SqlCommand cmd = new SqlCommand("select username, password from session_login where username=@username", con);
        cmd.Parameters.AddWithValue("@username", txtemail.Text);
        con.Open();
        using (SqlDataReader sdr = cmd.ExecuteReader())
        {

            if (sdr.Read())
            {
                username = sdr["username"].ToString();
                password = sdr["password"].ToString();
                MailMessage mm = new MailMessage("your email", txtemail.Text);
                mm.Subject = "Just Use For Demo!";
                mm.Body = string.Format("Hello: Your Password No is <h1>{0}</h1><br/> ", password);
                mm.IsBodyHtml = true;
                SmtpClient smtp = new SmtpClient();
                smtp.Host = "smtp.gmail.com";
                smtp.EnableSsl = true;
                NetworkCredential nc = new NetworkCredential();
                nc.UserName = "your email";
                nc.Password = "Your password";
                smtp.UseDefaultCredentials = true;
                smtp.Credentials = nc;
                smtp.Port = 25;
                smtp.Send(mm);
            }

        }
        con.Close();




    }
    protected void linkforget(object sender, EventArgs e)
    {
        Response.Redirect("ForgetPassword.aspx");
    }

}