SmtpException while sending mails from a particular mailing server - asp.net

Question

My question may be duplicate one, but i didn't got a proper solution for my problem.That's why i am asking.
I have a asp website.I am using smtpclient to send messages.My code is working fine with gmail settings.But in the production server they are using Bellnetwork's(smtp10.on.aibn.com) mailing server.They are using port 25 and also not using SSL(email provider doesn't support SSL).But the same mail settings was running fine for the last 2-3 years,but now when we send some messages from our site(production) 1 or 2 fails to send out and others will send out successfully.The strange thing is there was no problem for the last 3years.I am getting the following errors for the failed mails.
Exceptions:
1.
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.CheckCommand.Send(SmtpConnection conn, String& response)
at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, SmtpFailedRecipientException& exception)
at System.Net.Mail.SmtpClient.Send(MailMessage message)
--- End of inner exception stack trace ---
at System.Net.Mail.SmtpClient.Send(MailMessage message)
at Handler.BLL.cSendMail.SendMail(String p_strFrom, String p_strDisplayName, String p_strTo, String p_strSubject, String p_strMessage, String strFileName)
2.
System.IO.IOException: Unable to read data from the transport connection: net_io_connectionclosed.
3.
A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 67.69.240.69:25
System.Net.WebException: Unable to connect to the remote server ---> System.Net.Sockets.SocketException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond 67.69.240.69:25
at System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state, IAsyncResult asyncResult, Int32 timeout, Exception& exception)
--- End of inner exception stack trace ---
at System.Net.ServicePoint.GetConnection(PooledStream PooledStream, Object owner, Boolean async, IPAddress& address, Socket& abortSocket, Socket& abortSocket6, Int32 timeout)
at System.Net.PooledStream.Activate(Object owningObject, Boolean async, Int32 timeout, GeneralAsyncDelegate asyncCallback)
at System.Net.PooledStream.Activate(Object owningObject, GeneralAsyncDelegate asyncCallback)
at System.Net.ConnectionPool.GetConnection(Object owningObject, GeneralAsyncDelegate asyncCallback, Int32 creationTimeout)
at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)
at System.Net.Mail.SmtpClient.Send(MailMessage message)
--- End of inner exception stack trace ---
at System.Net.Mail.SmtpClient.Send(MailMessage message)
at Handler.BLL.cSendMail.SendMail(String p_strFrom, String p_strDisplayName, String p_strTo, String p_strSubject, String p_strMessage, String strFileName)
my code:
public bool SendMail(string p_strFrom, string p_strDisplayName, string p_strTo, string p_strSubject, string p_strMessage , string strFileName)
{
try
{
p_strDisplayName = _DisplayName;
string smtpserver = _SmtpServer;
SmtpClient smtpClient = new SmtpClient();
MailMessage message = new MailMessage();
MailAddress fromAddress = new MailAddress(_From,_DisplayName);
smtpClient.Host = _SmtpServer;
smtpClient.Port = Convert.ToInt32(_Port);
string strAuth_UserName = _UserName;
string strAuth_Password = _Password;
if (strAuth_UserName != null)
{
System.Net.NetworkCredential SMTPUserInfo = new System.Net.NetworkCredential(strAuth_UserName, strAuth_Password);
smtpClient.UseDefaultCredentials = false;
if (_SSL)
{
smtpClient.EnableSsl = true;
}
smtpClient.Credentials = SMTPUserInfo;
}
message.From = fromAddress;
message.Subject = p_strSubject;
message.IsBodyHtml = true;
message.Body = p_strMessage;
message.To.Add(p_strTo);
try
{
smtpClient.Send(message);
return true;
}
catch (SmtpException ee)
{
Log.WriteSpecialLog("smtpClient mail sending first try failed : " + ee.ToString(),"");
Log.WriteSpecialLog("status code : " + ee.StatusCode, "");
}
}

Answer 1

This code is working for me
public static string sendMail(string fromEmail, string toEmail, string subject, string body, string Name, string bcc="" , string replyTo="")
{
MailMessage mailer = new MailMessage
{
IsBodyHtml = true,
From = new MailAddress(fromEmail, "yoursite.com"),
Subject = subject,
Body = body,
BodyEncoding = Encoding.GetEncoding("utf-8")
};
mailer.To.Add(new MailAddress(toEmail, toEmail));
//
if (!string.IsNullOrEmpty(bcc))
{
mailer.Bcc.Add(bcc);
}
//
if (!string.IsNullOrEmpty(replyTo))
{
mailer.Headers.Add("Reply-To", replyTo);
}
//
AlternateView plainView = AlternateView.CreateAlternateViewFromString(Regex.Replace(body, "<(.|\\n)*?>", string.Empty), null, "text/plain");
AlternateView htmlView = AlternateView.CreateAlternateViewFromString(body, null, "text/html");
mailer.AlternateViews.Add(plainView);
mailer.AlternateViews.Add(htmlView);
SmtpClient smtp = new SmtpClient(ConfigurationManager.AppSettings["SMTPserver"]);
smtp.DeliveryMethod = SmtpDeliveryMethod.Network;
//smtp.DeliveryMethod = SmtpDeliveryMethod.PickupDirectoryFromIis;
NetworkCredential basicAuthenticationInfo = new NetworkCredential(ConfigurationManager.AppSettings["passMail"], ConfigurationManager.AppSettings["passKey"]);
smtp.UseDefaultCredentials = false;
smtp.Credentials = basicAuthenticationInfo;
smtp.EnableSsl = false;
smtp.Port = ConfigurationManager.AppSettings["Port"];
//
try
{
smtp.Send(mailer);
return "Email sent successfully !";
}
catch (Exception ex)
{
return "Failure in Email Message= !" + ex.message;
}
}