App preview on android with Esp8266

I just tryed to use Export_demo\Template_esp8266 app with esp01 and my Android phone, but impossible to complet the “Final check” on the Android app?

when I click the Preview button it completes wifi conneciton of the esp01 and cloud connection but can not succed finalize step.

what I see in serail monitor is as follows:

, epc3=0x00000000, excvaddr=0x00000000, depc=0x00000000
Fatal exception (0): 
epc1=0x400ef424, epc2=0x00000000, epc3=0x00000000, excvaddr=0x00000000, depc=0x00000000
Fatal exception (0): 

my arduino code is as follows:


#define USE_SPARKFUN_BLYNK_BOARD    // Uncomment the board you are using
//#define USE_NODE_MCU_BOARD        // Comment out the boards you are not using
//#define USE_CUSTOM_BOARD          // See "Custom board configuration" in Settings.h

#define APP_DEBUG        // Comment this out to disable debug prints

#define BLYNK_PRINT Serial
#include <BlynkSimpleEsp8266.h>
#include "BlynkProvisioning.h"

void setup() {



void loop() {
  // This handles the network and cloud connection;


Any idea who succeed in app preview with esp8266 really appriciated.

You would need to select custom board if you are using an ESP01 not the Blynk board. Then check the BlynkProvisioning.h file for the correct pin settings etc.

Hello and Welcome to the Blynk Forum.

I edited your post to format the code for viewability, as per Welcome Topic.
Please take note on how, for future posting. Thanks.

Thanks for your response.
Actually I tried with custom board , but no success.
By defining LED_PIN as 2 and BUTTON_PIN as 0.

    #if defined(USE_CUSTOM_BOARD)

      // Custom board configuration
      #define BOARD_BUTTON_PIN            0                     // Pin where user button is attached
      #define BOARD_BUTTON_ACTIVE_LOW     true                  // true if button is "active-low"

      #define BOARD_LED_PIN               2                     // Set LED pin - if you have a single-color LED attached
      //#define BOARD_LED_PIN_R           15                    // Set R,G,B pins - if your LED is PWM RGB 
      //#define BOARD_LED_PIN_G           12
      //#define BOARD_LED_PIN_B           13
      //#define BOARD_LED_PIN_WS2812      4                     // Set if your LED is WS2812 RGB
      #define BOARD_LED_INVERSE           false                 // true, if you need to inverse LED signal
      #define BOARD_RGB_BRIGHTNESS        32                    // 0..255 brightness control

@Serkan_Demirhan probably you need to use #define USE_NODE_MCU_BOARD and not SparkFun board. @vshymanskyy am I right?

@Serkan_Demirhan for the WeMos rather than the ESP01’s we use CUSTOM_BOARD but we changed the default BUTTON_PIN from 0 to 4. I think we found the special pin 0 was messing up other things in our sketch like OTA etc.

Obviously with the limited ESP-01 you can’t use pin 4 but you could play around with pins 1 and 3 (TX and RX). This would involve connecting and disconnecting wires etc as they are required for flashing.

Do you have the full set of headers in your sketch such as BlynkState.h, ConfigMde.h, etc?

Edit: I guess you must have all the headers or the sketch wouldn’t compile, right?