My Blynk App does not connect to my Arduino Mega

I am using Dragino-Yun shield on Arduino Mega2560. Following is the process I have gone through;

  1. When I first powered up the Dragino-Yun, its wifi ip-address was
  2. I configured Dragino-Yun shield to connect to my wifi modem (wifi ID & WPA password) and restarted
  3. IP-address is assigned to Dragino-Yun by the wifi modem
  4. I connected DHT11 sensor output to pin 21
  5. I created a sketch (DraginoDht11.ino) which sends DHT11 humidity & temperature data to the console every 2 seconds
  6. It worked fine
  7. I created a Blynk App and placed two Gauges on it (at V5 & V6) to receive and display temperature & humidity values from my Arduino sketch
  8. Now I created another sketch (BlynkDht11.ino) to send data to the Blynk App running on my Samsung Tablet which is connected to the same wifi modem
  9. I copied the authorization code to the sketch
  10. Sketch compiled and downloaded to the Arduino Mega2560 through wifi modem using Dragino-Yun shield
  11. Now when I run the App it says “Your Arduino Mega is not in network”

I tried hard but failed to understand what I am doing wrong.

My DraginoDht11.ino code is as under;

#include <Console.h>
#include "DHT.h"

#define DHTPIN 21           // what pin we're connected to
#define DHTTYPE DHT11       // DHT 11 

const int ledPin = 13; // the pin that the LED is attached to
int incomingByte;      // a variable to read incoming serial data into
uint16_t sNo;          // Serial number of reading

DHT dht(DHTPIN, DHTTYPE);   // Initialize DHT sensor for normal 16mhz Arduino

void setup() {
  // initialize serial communication:

  while (!Console){
    ; // wait for Console port to connect.
  Console.println("You're connected to the Console!!!!\n\r");
  Console.println("DHTxx test!");
  pinMode(13, OUTPUT);

void loop() {


  // Reading temperature or humidity takes about 250 milliseconds!
  // Sensor readings may also be up to 2 seconds 'old' (its a very slow sensor)
  float h = dht.readHumidity();
  // Read temperature as Celsius
  float t = dht.readTemperature();
  // Read temperature as Fahrenheit
  float f = dht.readTemperature(true);
  // Check if any reads failed and exit early (to try again).
  if (isnan(h) || isnan(t) || isnan(f)) {
    Console.println("Failed to read from DHT sensor!");

  // Compute heat index
  // Must send in temp in Fahrenheit!
  float hi = dht.computeHeatIndex(f, h);
  Console.print(". Humidity: "); 
  Console.print(" %\t");
  Console.print("Temperature: "); 
  Console.print(" *C ");
  Console.print(" *F\t");
  Console.print("Heat index: ");
  Console.println(" *F");

My BlynkDht11.ino code is as under;

#define BLYNK_PRINT Serial    // Comment this out to disable prints and save space
#include <SPI.h>
#include <Ethernet.h>
#include <BlynkSimpleEthernet.h>
#include <SimpleTimer.h>
#include <DHT.h>

char auth[] = "********************************";

#define DHTPIN 21          // What digital pin we're connected to
#define DHTTYPE DHT11     // DHT 11

SimpleTimer timer;

void sendSensor()
  float h = dht.readHumidity();
  float t = dht.readTemperature(); // or dht.readTemperature(true) for Fahrenheit

  if (isnan(h) || isnan(t)) {
    Serial.println("Failed to read from DHT sensor!");
  Blynk.virtualWrite(V5, h);
  Blynk.virtualWrite(V6, t);

void setup()
  // initialize serial communication:
  Serial.begin(9600); // See the connection status in Serial Monitor


  // Setup a function to be called every 2 second
  timer.setInterval(2000L, sendSensor);

void loop()
{; // Initiates Blynk; // Initiates SimpleTimer

After further detailed analysis of the DSL router and DHCP server within it, it seemed that, apparently, there is no problem on network side. My Wifi supports WPA & WPA2, There is no active firewall on the router. But when I try to connect my Windows10 computer through TELNET to, it simply says “Connection to host lost”. Following are some screenshots. RBB is the Dragino Yun identity in the DSL wifi modem’s DHCP client.

Further attaching Dragino-Yun configuration screenshots

No one seems to have any suggestions about my problem :unamused:

only @vshymanskyy may know if that shield is supported.

Also did you try simplest possible sketch without DHT?

Thanks for the reply. I didn’t know if there is some issue with Dragino-Yun shield. However, I did try the simplest on/off first. It didn’t work either.

In my 2nd post, I included a screenshot of my telnet session in which there is no response from the Is this normal behavior for a general telnet request?