My ASP.NET application that has been working without any problems for a long time started giving an error. The error seems to be starting with the application trying to send an email message. From the error message the custom sent me it looks like something to do with the System.Net.Sockets. Any idea of what might be causing this problem?

Thank you. Below is a copy of the error message:

[SocketException (0x2745): An established connection was aborted by the software
in your host machine]
   System.Net.Sockets.Socket.DoConnect(EndPoint endPointSnapshot, SocketAddress
socketAddress) +1002146
   System.Net.Sockets.Socket.InternalConnect(EndPoint remoteEP) +33
   System.Net.ServicePoint.ConnectSocketInternal(Boolean connectFailure, Socket
s4, Socket s6, Socket& socket, IPAddress& address, ConnectSocketState state,
IAsyncResult asyncResult, Int32 timeout, Exception& exception) +431

[WebException: Unable to connect to the remote server]
   System.Net.ServicePoint.GetConnection(PooledStream PooledStream, Object
owner, Boolean async, IPAddress& address, Socket& abortSocket, Socket&
abortSocket6, Int32 timeout) +1447736
   System.Net.PooledStream.Activate(Object owningObject, Boolean async, Int32
timeout, GeneralAsyncDelegate asyncCallback) +190
   System.Net.PooledStream.Activate(Object owningObject, GeneralAsyncDelegate
asyncCallback) +21
   System.Net.ConnectionPool.GetConnection(Object owningObject,
GeneralAsyncDelegate asyncCallback, Int32 creationTimeout) +318
   System.Net.Mail.SmtpConnection.GetConnection(String host, Int32 port) +227
   System.Net.Mail.SmtpTransport.GetConnection(String host, Int32 port) +316
   System.Net.Mail.SmtpClient.GetConnection() +42
   System.Net.Mail.SmtpClient.Send(MailMessage message) +1485