Arduino UNO W5100 disconnect after 5 second!

Solved
1

Hi friends. I upload the below code from the blynk examples sketch to the arduino UNO with W5100 shield but after 5 second disconnected from the server !

the sketch:

#define BLYNK_PRINT Serial


#include <SPI.h>
#include <Ethernet.h>
#include <BlynkSimpleEthernet.h>

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "e5aac1087ca142ceaab95e9ad3198d6e";

// Your WiFi credentials.
// Set password to "" for open networks.
char server[] = "10.5.51.5";

// Select your pin with physical button
const int btnPin = 11;

WidgetLED led3(V3);

BlynkTimer timer;

// V3 LED Widget represents the physical button state
boolean btnState = false;
void buttonLedWidget()
{
  // Read button
  boolean isPressed = (digitalRead(btnPin) == LOW);

  // If state has changed...
  if (isPressed != btnState) {
    if (isPressed) {
      led3.on();
    } else {
      led3.off();
    }
    btnState = isPressed;
  }
}

void setup()
{
  // Debug console
  Serial.begin(9600);

  Blynk.begin(auth, server, 8080);
  // You can also specify server:
  //Blynk.begin(auth, ssid, pass, "blynk-cloud.com", 8442);
  //Blynk.begin(auth, ssid, pass, IPAddress(192,168,1,100), 8442);

  // Setup physical button pin (active low)
  pinMode(btnPin, INPUT_PULLUP);

  timer.setInterval(500L, buttonLedWidget);
}

void loop()
{
  Blynk.run();
  timer.run();
}

the serial monitor log:

[0] Getting IP...
[5524] IP:10.5.51.9
[5524] 
    ___  __          __
   / _ )/ /_ _____  / /__
  / _  / / // / _ \/  '_/
 /____/_/\_, /_//_/_/\_\
        /___/ v0.5.4 on Arduino Uno

[5638] Connecting to 10.5.51.5:8080
[5688] Ready (ping: 9ms).
[10757] Connecting to 10.5.51.5:8080
[15758] Connecting to 10.5.51.5:8080
[20759] Connecting to 10.5.51.5:8080
2

Problem solved by using pin 8 in const int btnPin = ;

3