I just noticed that some of the email operations in my code have been failing and am trying to fix it up, however I keep getting the following error:
System.Net.Mail.SmtpException: Failure sending mail. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host.
---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
at System.Net.Sockets.Socket.Receive(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags)
at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
--- End of inner exception stack trace ---
at System.Net.Sockets.NetworkStream.Read(Byte[] buffer, Int32 offset, Int32 size)
at System.Net.DelegatedStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at System.Net.BufferedReadStream.Read(Byte[] buffer, Int32 offset, Int32 count)
at System.Net.Mail.SmtpReplyReaderFactory.ReadLines(SmtpReplyReader caller, Boolean oneLine)
at System.Net.Mail.SmtpReplyReaderFactory.ReadLine(SmtpReplyReader caller)
at System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port)
at System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port)
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)
My code is fairly straightforward:
MailMessage mail = new MailMessage();
mail.To.Add(email_to);
mail.From = new MailAddress(email_from);
mail.Subject = email_subject;
mail.Body = email_body;
var client = new SmtpClient(smtp_server_url);
client.Credentials = new NetworkCredential(username, password, domain);
client.Timeout = 30000;
client.Send(mail);
Does anyone have any ideas what could be going on? Our exchange server administrator says she can't see anything in the log.
Also, not that this is a surprise, but the same thing happens when I try to send a message from powershell.