mail not firing from windows application tool

Question

Email not firing from windows application tool from a particular network but from other networks its working file i placed my code below.

 

private void button1_Click(object sender, EventArgs e)

{

StringBuilder sb = new StringBuilder();

try

{

MailMessage m = new MailMessage();

sb = new StringBuilder();

m.From = new MailAddress("[email protected]");

m.To.Add(new MailAddress("[email protected]"));

string SUBJECT = string.Empty;

SUBJECT = "TestMail";

sb.Append("Hi Its a test mail <b/><br/><br/>");

m.Subject = SUBJECT;

m.Body = sb.ToString();

m.IsBodyHtml = true;

SmtpClient smtp = new SmtpClient();

smtp.Host = "mail.verbinden.in";

smtp.Port = 587;

smtp.UseDefaultCredentials = false;

smtp.EnableSsl = true;

smtp.Timeout = 80000;

smtp.Credentials = new System.Net.NetworkCredential("[email protected]", "Noreply123$");

smtp.Send(m);

MessageBox.Show("Email has been send");

}

catch (Exception ex)

{

MessageBox.Show(ex.ToString());

}

}