TCP/IP communication between Arduino and Simulink

I am trying to set up a WiFi communication between my Arduino Yun and my PC, I have to use Matlab /simulink for that. I already connected the Yun to my WiFi network, it has the Ip Address 192.168.2.105, my Pc has the IP Adress 192.168.2.103. I found this example for a TCP/IP communication in the arduino forum, which I am running on the Yun:

#include <Bridge.h>
#include <YunClient.h>

#define PORT 80

// Define our client object
YunClient client;

void setup()
{
  // Bridge startup
  Bridge.begin();

    Serial.begin(9600);

    while (!Serial); // wait for a serial connectionM
  }

void loop()
{
  // Make the client connect to the desired server and port
  IPAddress addr(192, 168, 2, 103);

    // Or define it using a single unsigned 32 bit value
    // IPAddress addr(0xc0a8sab9); // same as 192.168.42.185

    // Or define it using a byte array
    // const uint8 addrBytes = {192, 168, 42, 185};
    // IPAddress addr(addrBytes);

    client.connect(addr, PORT);

    // Or connect by a server name and port.
    // Note that the Yun doesn't support mDNS by default, so "Yun.local" won't work
    // client.connect("ServerName.com", PORT);

    if (client.connected())
    {
      Serial.println("Connected to the server.");

      // Send something to the client
      //client.println("Something...");
      client.println(3);
      // Cheap way to give the server time to respond.
      // A real application (as opposed to this simple example) will want to be more intelligent about this.
      delay (250);

      // Read all incoming bytes available from the server and print them
      while (client.available())
      {
        char c = client.read();
        Serial.print(c);
      }
      Serial.flush();

      // Close the connection
      client.stop();
    }
    else
      Serial.println("Could not connect to the server.");  

    // Give some time before trying again
    delay (10000);
  }

In Simulink I use the TCP/IP receive und TCP/IP send blocks from the Instrument toolbox in the model attached, but I am always getting the error message:

Error evaluating registered method 'Start' of MATLAB S-Function 'stcpiprb' in 'host_receive/TCP//IP Receive'.
Caused by:
Unsuccessful open: Connection timed out: connect

I would expect, that the sketch and simulink would create a echo, starting with 2 and getting doubled every time.

I don't know a lot about Wifi and TCP/IP communication and I am not sure if this is the right forum for this problem, but maybe someone can help me with the simulink part. Is the problem on the Simulink or the Arduino side?