Debug output ceases after successful wifi connection

Hello! I am having an issue connecting to Blynk’s cloud server with my Arduino Nano + ESP8266 shield project. According to the debug output, the device successfully connects to the WiFi network but then ceases to print anything else.

According to Dmitriy at Blynk, they are not experiencing any outages on their end. Any ideas what could be the issue?

Blynk Debug output:

[2751] Connecting to WiFi_SSID
[5838] AT version: 5 2017 16:10:59)
SDK version:2.1.0(116b762)
compile time:May 5 2017 16:37:48
[9023] +CIFSR:STAIP,“”
[9097] Connected to WiFi

Project details:
• Hardware & communication: RobotDyn Nano V3 (ATmega328p) with ESP8266 Shield
• Smartphone OS: Android version 9
• Server: Blynk Cloud
• Blynk Library version: 0.5.3

#define BLYNK_PRINT DebugSerial
#include <SoftwareSerial.h>
SoftwareSerial DebugSerial(2, 3); // TTL-USB adapter wired to 2, 3, GND

#include <ESP8266_Lib.h>
#include <BlynkSimpleShieldEsp8266.h>

char auth[] = "Blynk_Auth";
char ssid[] = "WiFi_SSID";
char pass[] = "WiFi_PASS";

#define EspSerial Serial // ESP8266 Serial wired to 0, 1
#define ESP8266_BAUD 115200
ESP8266 wifi(&EspSerial);

void setup()
  DebugSerial.begin(9600); // Debug console

  EspSerial.begin(ESP8266_BAUD); // ESP8266 shield

  Blynk.begin(auth, wifi, ssid, pass);

void loop()

That is NOT Blynk debug info, that looks like standard ESP startup data… if you want actual Blynk Debug you need to initialize it…

Thank you for your feedback. I was basing my approach on the Arduino_Serial_USB example as instructed in this post: Serial Debug for Arduino UNO connected on USB

Seeing the documentation you shared, I thought I’d rewire the Debug Serial to my Nano’s Serial and the ESP8266 to a SoftwareSerial. Adding in the BLYNK_DEBUG definition now gives a slightly more detailed output, but still halts after connection:

[688] Connecting to WiFi_SSID
AT wersion: 5 2017 16:10:i2
[17804] +CIFSR:STAIP,“”

[17815] Connected to WiFi

*Note: I am powering the device directly from a power supply, so I don’t expect any interference on the Debug serial bus.

Updated code segment (first lines of script):

#define BLYNK_PRINT Serial

#include <SoftwareSerial.h>
SoftwareSerial EspSerial(2, 3); // RX, TX

This might (but not necessary IS) the issue. I don’t know if Blynk has been “approved” to work with this AT version. There might be different response format (for example), which library can’t handle. For me SDK 2.0.0 is working fine now, but I do remember I do have issues with that too. modifying a library a bit fixed that issue.

Thanks for the suggestion. I rolled back the ESP8266 SDK to v2.0.0 and inserted that wifi disconnect line into the Blynk library, but they were ineffective. Here is the resulting output:

[771] Disconnect from previous Wifi AP
[1312] Connecting to WiFi_SSID
[4396] AT version: 14 2016 18:54:01)
SDK version:2.0.0(656edbf)
compile time:Jul 19 2016 18:44:44
[10658] +CIFSR:STAIP,“”
[10733] Connected to WiFi