C# socket.beginsend does not send data the second time

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C#

C#4.0

I am connected to a TCP server, and constantly have to send data to the server. I am sending data asynchronously, using the socket.BeginSend method. The first attempt at sending the data is successfull, but there after anything that I try to send does not get delivered to the server. It acts almost as if the Socket is disconeected, but I do check for that, and it is not disconnected. I have no idea of what can cause this, so any help or suggestions would be appreciated.

sending method:

public virtual void SendPDU(byte[] PDU)
        {
            try
            {
                if (socket.Connected)
                {
                    Console.WriteLine("Sending: " + PDU.ToString());
                    socket.BeginSend(PDU, 0, PDU.Length, SocketFlags.None, new AsyncCallback(SendCallback), socket);
                }
                else
                {
                    
                    Console.WriteLine("Socket is not connected to a SMSC");
                    
                }
            }
            catch (Exception e)
            { 
                ExceptionLogger.Logg(e);
                Console.WriteLine("***********Exception Logged***********");
            }
        }

Here is the callback delegate:

private void SendCallback(IAsyncResult ar)
        {
            try
            {
                Socket clientSocket = (Socket)ar.AsyncState;

                int bytesSent = clientSocket.EndSend(ar);
                Console.WriteLine("Sent {0} bytes to SMSC", bytesSent);
                //clientSocket.Dispose();
            }
            catch (Exception e)
            {
                
                Console.WriteLine("***********Exception Logged***********");
                ExceptionLogger.Logg(e);
            }
        }