The server response was: 5.7.0 Authentication Required in C# web hosting website

Question

Recently I am working on sending mail by c# coding and I tryed to send mail by c# coding on visual studio platform and it's work totally fine in my localhost of visual studio. but when I run that same code over other hosting website like myASP.NET or Somee.com that time that code getting error.

error like (if I used smtp.gmail.com then error like

The SMTP server requires a secure connection or the client was not authenticated. The server response was: 5.7.0 Authentication Required. Learn more at)

and (if I used smtp.somee.com then error generate like

Failure sending mail.)

Sending mail Code in c# is,

String username = "";
      string password = "";
      OleDbConnection con = new OleDbConnection(ConfigurationManager.ConnectionStrings["cstring"].ConnectionString);
      OleDbCommand cmd = new OleDbCommand("select umail, lpwd from uregister where umail=@email", con);
      cmd.Parameters.AddWithValue("email", txtEmail.Text);
      con.Open();
      using(OleDbDataReader sdr = cmd.ExecuteReader()) {

          if (sdr.Read()) {
              username = sdr["umail"].ToString();
              password = sdr["lpwd"].ToString();

          }

      }
      con.Close();
         if (!string.IsNullOrEmpty(password)) {

            MailMessage Msg = new MailMessage();
              // Sender e-mail address.
              Msg.From = new MailAddress(txtEmail.Text);
              // Recipient e-mail address.
              Msg.To.Add(txtEmail.Text);
              Msg.Subject = "Your Password Details";
              Msg.Body = ("Your Username is:" + username + "<br/><br/>" + "Your Password is:" + password);
              Msg.IsBodyHtml = true;
              // your remote SMTP server IP.
               SmtpClient Smtp = new SmtpClient();
              Smtp.Host = "";
             Smtp.Port = 587;
            NetworkCredential ntwd = new NetworkCredential();
                    ntwd.UserName = "xyz@gmail.com"; //Your Email ID
          ntwd.Password = "xyz123."; // Your Password
            Smtp.UseDefaultCredentials = false;
          Smtp.Credentials = ntwd;

          Smtp.EnableSsl = true;
          Smtp.Send(Msg);

              lbltxt.Text = "Your Password Details Sent to your mail.";
              // Clear the textbox valuess
              txtEmail.Text = "";
          }
          else
          {
              lbltxt.Text = "The Email you entered not exists.";
          }

this code is not work on hosting site somee.com/myASP.NET. so please let me know what is problem in this code..

Answer 1

In your case, you should provide strong password as per domain policy.