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I have developed c# programe to send email alongwith pdf file attachement. when I run the programe it producs the error "unable to read data from the transport connection an existing connection was forcibly closed by remote host". I searched help of this error on internet but could not resolve the issue. I have also on the less secure option of gmail account. Please suggest any remedy.

What I have tried:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Net;
using System.Net.Mail;
using System.Web;

namespace MailMessaje
    public partial class Form1 : Form
        public Form1()
        private void btnSend_Click(object sender, EventArgs e)
                MailMessage mail = new MailMessage();
                SmtpClient client = new SmtpClient();
                mail.From = new MailAddress("<email>");
                mail.Subject = this.txtSubjectMail.Text;
                mail.Body = this.txtBodyMail.Text;
                System.Net.Mail.Attachment attachFile = new Attachment("D:\\exp1.pdf");

                client.Port = 587;
                client.Host = "";
                client.DeliveryMethod = SmtpDeliveryMethod.Network;
                client.EnableSsl = true;
                client.Credentials = new System.Net.NetworkCredential("<email>", "<password>");
                System.Net.ServicePointManager.Expect100Continue = false;

                MessageBox.Show("Message Send Successfully");
            catch (Exception ex)
Updated 15-Oct-18 1:31am
Afzaal Ahmad Zeeshan 15-Oct-18 6:31am    
Never share your email/password on the internet. It is not a safe place to share such information. We only require the code that you are using and can try out with our own username/password if needed for a test.
F-ES Sitecore 15-Oct-18 6:43am    
This question is asked almost every day. Google for how to send email through gmail and you'll find thousands of results that will explain the issues you might face. Ultimately you shouldn't send email through gmail at all, you should use the smtp server supplied by your webhost.

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