I cannot Blynk App open "Couldn't connect to the server. Check your internet connection and try again."

I couldn’t set my latest(first) Project in Blynk App(Android), so I deleted it.
It would now try again. I could the App downloaded. But can not open. I see under i button (About), that my Email Adress is there as Account.
The Message is: “Couldn’t connect to the server. Check your internet connection and try again.”

I tried from my Wife’s Smartphone to connect (new Account, new Projekt), I got an IP Adresse for my Datastream (I see in Arduino Serial Monitor), but these can not open. And come no Data thru. In App write: No Data yet…
The same Problem as with my Account?

Please help!

Maybe it would be better if you described your issues in your native language and allow us to use an online translation service.

Screenshots of your app, plus your code (correctly formatted of course) and the output from your serial monitor, would probably be helpful too.


Ich arbeite auf einem Projekt für Espressomaschine. Ich kam mit dem Blynk nicht klar, deshalb habe ich es gelöscht.
Jetzt möchte ich wieder probieren. Ich kann das App auf meinem Handy herunterladen. Aber wenn ich auf dem Icon Blynk tippe, öffnet sich das App nicht. Nach langer Wartezeit kommt folgender Nachrichten:

Have you tried restarting your phone?
And maybe deleting and re-installing the app?

You seemed to say earlier that the app opened successfully on your wife’s phone.
If this is the case then it clearly points to an issue with your phone.


Hi Pete,
I did it more Times (Restarting). On my Wife’s Phone is another Account.

I could Log out. And Log in again. That’s work! Yuppie. Problem solved (for the Moment)

Thanks for Helping

Auth. Token ist OK. Pin setting OK.
What is Wrong? Why see I nothing?
There is a Max6675 Sensor, what work well in other Setting.

Impossible to say without seeing your code.


Download latest Blynk library here:

Blynk is a platform with iOS and Android apps to control
Arduino, Raspberry Pi and the likes over the Internet.
You can easily build graphic interfaces for all your
projects by simply dragging and dropping widgets.

Downloads, docs, tutorials: http://www.blynk.cc
Sketch generator:           http://examples.blynk.cc
Blynk community:            http://community.blynk.cc
Follow us:                  http://www.fb.com/blynkapp

Blynk library is licensed under MIT license
This example code is in public domain.

This example shows how to send values to the Blynk App,
when there is a widget, attached to the Virtual Pin and it
is set to some frequency

Project setup in the app:
Value Display widget attached to V7. Set any reading
frequency (i.e. 1 second)

/* Comment this out to disable prints and save space */

#define BLYNK_PRINT Serial`
#include <ESP8266WiFi.h>
#include <BlynkSimpleEsp8266.h>
#include "max6675.h"

// You should get Auth Token in the Blynk App.
// Go to the Project Settings (nut icon).
char auth[] = "aeLJ6vcwMfDlKwniyrk_oFjVjhxxxx";

// Your WiFi credentials.
// Set password to "" for open networks.
char ssid[] = "WLAN-589548";
char pass[] = "65427253414xxxx";

// Use Virtual pin 7 for uptime display
#define PIN_UPTIME V7

// This function tells Arduino what to do if there is a Widget
// which is requesting data for Virtual Pin (7)
 int thermoCLK = D8;
int thermoCS = D7;
int thermoDO = D6;
MAX6675 thermocouple(thermoCLK, thermoCS, thermoDO);
float tempC, tempF, tempK;
char type='C';//default temperature type C
// This command writes Arduino's uptime in seconds to Virtual Pin (7)
  Blynk.virtualWrite(PIN_UPTIME,'C' / 1000);

void setup()
  // Debug console

  Blynk.begin(auth, ssid, pass);
  // You can also specify server:
  //Blynk.begin(auth, ssid, pass, "blynk-cloud.com", 80);
  //Blynk.begin(auth, ssid, pass, IPAddress(192,168,1,100), 8080);

void loop()


@balolevi please edit your post, using the pencil icon at the bottom, and add triple backticks at the beginning and end of your code so that it displays correctly.
Triple backticks look like this:


I did it

Okay, so you’re setting up your MAX6675 object, which seems to be called thermocouple, here:

And three float variables to hold the temperature readings in Celsius, Fahrenheit and Kelvin…

But you are never taking a temperature reading, or sending the result of that reading to Blynk.

You appear to have decided to create a new variable called C but you’ve not understood how to do that correctly, as the variable you created is actually called type

I’d suggest that you go back to the original code and try to understand it better.

I’d also stay away from using Blynk widgets to trigger the readings (avoid BLYNK_READ) and instead use a timer to call the routine which takes the readings. Printing those readings to your serial monitor is also a good move, as it allows you to know that your sensor is actually working correctly.


Thanks a lot Pete for your Answer. I’ll try it.