Tcp/IP socket programming client application stops responding after few request

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C#4.0

ASP.NET4

The TCP/IP socket web application is not responding after few request .

What I have tried:

Our company manufactures weighing scales.I have developed a programmed that communicates with the scale and get the current weight data back.The scale has a LAN card that enable us to communicate using TCP/IP socket Programming.The Scale is been provided an ip address and a port number (acts as a server).I have developed a web application that communicate with the device connect in a lan network and get the weighing data back.

public void TcpClientScale()
        {
            if (!System.IO.Directory.Exists("c://EssaeLog"))
            {
                System.IO.Directory.CreateDirectory("c://EssaeLog");
            }
            string path ="c://EssaeLog//"+ DateTime.Now.ToString("dd-MM-yyyy") + ".txt";
            TcpClient tc = new TcpClient();
            try
            {
                NetworkStream ns = null;
                tc.Connect(IP, int.Parse(PORT));
                byte[] myArray = new byte[100];
                int value = Convert.ToInt32("5", 16);
                string stringValue = Char.ConvertFromUtf32(value);
                ns = tc.GetStream();
                tc.SendTimeout = 2000;
                tc.ReceiveTimeout = 2000;               
                byte[] tosendbytes = Encoding.ASCII.GetBytes((stringValue));
                ns.Write(tosendbytes, 0, tosendbytes.Length);                
                int no = ns.Read(myArray, 0, 100);             
                string str = System.Text.Encoding.ASCII.GetString(myArray);//getting the result and storing it in a string//                
                str = str.Substring(0, no);//checking and removing any unwanted garbage value if any //
                Result = str;                
                File.AppendAllText(path, "-------------> Recieved Successfully @" + DateTime.Now.ToString() + Environment.NewLine );
            }
            catch(Exception ex)
            {
                File.AppendAllText(path, Environment.NewLine + "-------------> Error @" + DateTime.Now.ToString() + Environment.NewLine + ex.ToString() + Environment.NewLine + Environment.NewLine);
            }
            finally
            {
                tc.Close();  
                Dispose();    
            }
        }

I am using IIS as server and publishing the web app.The problem that I am facing is ,after few requests the machine is not responding back and the webpages seems to be hanging .I have checked the machine using Hyper-terminal there is no problem with the machine.I think there is some problem with the code .Please help me what I am doing wrong.

UPDATE :

I have update the code with proper try catch .Now I am getting the following error in the log file.

System.IO.IOException: Unable to read data from the transport connection: 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. ---> 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
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 Scale.GetWeight.TcpClientScale() in C:\Users\Demo\Desktop\Pranav\LandMark Issue\VolumetricScale\Source\Scale\Scale\GetWeight.aspx.cs:line 92

UPDATE :

Another error that i am getting after few request .

System.Net.Sockets.SocketException (0x80004005): No connection could be made because the target machine actively refused it 172.21.201.229:4321
at System.Net.Sockets.TcpClient.Connect(String hostname, Int32 port)
at Scale.GetWeight.TcpClientScale() in C:\Users\Demo\Desktop\Pranav\LandMark Issue\VolumetricScale\Source\Scale\Scale\GetWeight.aspx.cs:line 84

after few minutes the application starts workiing again for sometimes and then i am getting the same error again .Please help me out that what is causing this problem