C# Socket in Unity (in ClientSocket : MonoBehaviour) does not receive server package(s) (keeps losing).

Hi! Sorry for my English!

I have C# AsyncServer. It sends packages to Unity client. Unity client has ClientSocket : MonoBehaviour on scene. SocketController receives packages quite well, but sometimes Unity (ClientSocket) does not receive some server packages (no errors in package receiving in parsing -100%).

Antivirus switched on/off. Port is allowed. Changed send package delay time on server (from 1 to 200 ms).

No error! No warnings (there are my debug warnings)! Nothing! Silence - just no packages!

Socket Receiving Method:

 private Socket _clientSocket = new Socket(
         AddressFamily.InterNetwork,
         SocketType.Stream,
         ProtocolType.Tcp
 );
 
 private byte[] _recieveBuffer = new byte[32768];
 
 private void ReceiveCallback(IAsyncResult ar) {
 
          int recieved = _clientSocket.EndReceive(ar);
 
          byte[] recData = new byte[recieved];
 
           Buffer.BlockCopy(
               _recieveBuffer,
               0,
              recData,
               0,
               recieved
         );
 
        Receive();
 }
 
 private void Receive() {       
 
         _clientSocket.BeginReceive(
             _recieveBuffer,
             0,
             _recieveBuffer.Length,
             SocketFlags.None,
             new AsyncCallback(ReceiveCallback),
             _clientSocket
         );
 
 }

This is very annoying situation, because Unity reports nothing! I do not know what to do. Should I use Socket.ReceiveAsync(SocketAsyncEventArgs) or other methods? I would like to find out what's happening.

Thanks!