Failed to connect using DNS server

Question

Previously I had problem to connecting my client and server using DNS Server, because I could not solve the ip,

public static TcpClient client;
        private const int _PORT = 100; // same as server port
        public static string connectTo = "kamikazehc.ddns.net";
        public static IPAddress ipaddress = null;

resolving IP addresses into DNS name:

   private static void ConnectToServer()
            {

                int attempts = 0;

                bool IsValidIP = IPAddress.TryParse(connectTo, out ipaddress);
                if (IsValidIP == false)
                {
                    ipaddress = Dns.GetHostAddresses(connectTo)[0];
                    Console.WriteLine(Dns.GetHostAddresses(connectTo)[0]);
                }
                client = new TcpClient();

                while (!_clientSocket.Connected)
                {
                    try
                    {
                        attempts++;
                        Console.WriteLine("Connection attempt " + attempts);
                        _clientSocket.Connect(ipaddress, _PORT);
                        Thread.Sleep(100);

                    }
                    catch (SocketException)
                    {
                        Console.Clear();
                    }
                    }
                Console.Clear();
                Console.WriteLine("Connected");

            }

If I put my local Ip 192.168.x.x I connect. But if I use my fixed IP or dns the client makes endless attempts to connect.

Using DNS or Fixed IP

Using local IP:

I would like to know how to solve this to be able to connect, I imagine I do not need to modify the code, just configure my internet, but I do not know how to configure