Error Failure sending mail with smtpexception

Question

I am trying to send email via my web, I research for help no luck. Still receive error: smtpexception was unhandled by user code

 protected void Button1_Click(object sender, EventArgs e)
    {

        MailMessage msg = new MailMessage();
        msg.From = new MailAddress("[email protected]");
        msg.To.Add(TextBox3.Text);
        msg.Subject = TextBox4.Text;
        msg.Body = TextBox5.Text;
        msg.IsBodyHtml = true;

        SmtpClient smtp = new SmtpClient();
        smtp.Host = "smtp.gmail.com";

        System.Net.NetworkCredential netCred = new System.Net.NetworkCredential();
        netCred.UserName = "[email protected]";
        netCred.Password = "11111111";

        smtp.UseDefaultCredentials = true;
        smtp.Credentials = netCred;
        smtp.Port = 465;
        smtp.EnableSsl = true;
        smtp.Send(msg);
        try
        {
            smtp.Send(msg);
            Label1.Text = "Your E-Mail Sent Great Job!!!!";
        }
        catch (Exception ex)
        {
            //Handle your exception here
            Label1.Text = ex.Message + " " + "Oeps, something when wrong when we tried to send the email";
            return;
        }           
    }

when i run it shows me this error highlighting smtp.Send(message);:

SmtpException was unhandled by the user code and Failure sending mail.

System.Net.Mail.SmtpException: Failure sending mail. ---> System.IO.IOException: Unable to read data from the transport connection: net_io_connectionclosed. at System.Net.Mail.SmtpReplyReaderFactory.ProcessRead(Byte[] buffer, Int32 offset, Int32 read, Boolean readLine) at System.Net.Mail.SmtpReplyReaderFactory.ReadLines(SmtpReplyReader caller, Boolean oneLine) at System.Net.Mail.SmtpReplyReaderFactory.ReadLine(SmtpReplyReader caller) at System.Net.Mail.SmtpConnection.GetConnection(ServicePoint servicePoint) at System.Net.Mail.SmtpTransport.GetConnection(ServicePoint servicePoint) at System.Net.Mail.SmtpClient.GetConnection() at System.Net.Mail.SmtpClient.Send(MailMessage message) --- End of inner exception stack trace --- at System.Net.Mail.SmtpClient.Send(MailMessage message) at IntroAsp.net.EmailMsg.Button1_Click(Object sender, EventArgs e) in c:\Users\Regev\Documents\Visual Studio 2013\Projects\IntroAsp.net\IntroAsp.net\EmailMsg.aspx.cs:line 46

there should be much more to the exception detail than that, could you add it? — Crowcoder

Chotalia Namrata Chotalia Namrata · Accepted Answer · 2017-04-24T09:50:37

Possible solutions:

1) Make smtpClient.UseDefaultCredentials = false;

2) The credentials "UserName" and "Password" are valid for sending an email.

3) Check port 465 is not blocked by a firewall.

4) Instead of using port number 465 use port 587.

Hope, this might help you.

Thank you.

Error Failure sending mail with smtpexception

1 Answers