SNTP Client in C#

<pre> private void Initialize()
        {
            // Set version number to 4 and Mode to 3 (client)
            NTPData[0] = 0x1B;
            // Initialize all other fields with 0
            for (int i = 1; i < 48; i++)
            {
                NTPData[i] = 0;
            }
            // Initialize the transmit timestamp
            TransmitTimestamp = DateTime.Now;
        }

while (!messageReceived && (elapsedTime < TimeOutInterval))
{
    sendSocket.SendTo(SNTPData, SNTPData.Length, SocketFlags.None, sendEP); // I think this line must be out of the loop :) 
    // Check if data has been received by the listening socket and is available to be read
    if (sendSocket.Available > 0)
    {
        messageLength = sendSocket.ReceiveFrom(SNTPData, ref epSendEP);
        if (!IsResponseValid())
        {
            throw new Exception("Invalid response from " + TimeServer);
        }
        messageReceived = true;
        break;
    }
    // Wait a second
    Thread.Sleep(1000); // << 2 bug here!!! 
    elapsedTime += 1000;
}

IPEndPoint listenEP = new IPEndPoint(IPAddress.Any, 123);
                Socket sendSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
                IPHostEntry hostEntry = Dns.GetHostEntry(TimeServer);
                IPEndPoint sendEP = new IPEndPoint(hostEntry.AddressList[0], 123);
                EndPoint epSendEP = (EndPoint)sendEP;

                int messageLength = 0;
                try
                {
                    sendSocket.Bind(listenEP);