suggested use Asynchronous Programming(Async Task)

Server:

int connectCount = 0;
Console.WriteLine("wait for conncet...");
Socket tcpServer = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPAddress iPAddress = new IPAddress(new byte[] {192,168,2,103 });
IPEndPoint endPoint = new IPEndPoint(iPAddress, 7788);
tcpServer.Bind(endPoint);
tcpServer.Listen(100); 
var client= tcpServer.Accept();

Console.WriteLine($"conncet:{++connectCount}{client.AddressFamily.ToString()}");
byte[] data = new byte[1024];
int len= client.Receive(data);
Console.WriteLine(Encoding.UTF8.GetString(data,0,len));
string ServerMessage = "Server Send Message to Client";
Console.WriteLine($"Send:{ServerMessage}");
client.Send(Encoding.UTF8.GetBytes(ServerMessage));

client.Close();
tcpServer.Close();
Console.ReadLine();

Client:

using System.Net;
using System.Net.Sockets;
using System.Text;

Socket tcpClient = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
IPAddress iPAddress = new IPAddress(new byte[] { 192, 168, 2, 103 });//IP
IPEndPoint endPoint = new IPEndPoint(iPAddress, 7788);//port
tcpClient.Connect(endPoint); //connect
Console.WriteLine("connect..");
string sendMessage = "line";
Console.WriteLine($"send:{sendMessage}...");
tcpClient.Send(Encoding.UTF8.GetBytes(sendMessage));//send


byte[] data = new byte[1024];
int len = tcpClient.Receive(data);
Console.WriteLine($"Server:{Encoding.UTF8.GetString(data, 0, len)}");