Unable To Discover Devices in Alexa App

[karankadu]

Recently I have tried weenymo.ino, Program Successfully compiled and uploaded to ESP8266. After running on the serial monitor "TELL ALEXA TO DISCOVER DEVICES" also printed as per program. But my Alexa app could find any device. I have a default Program you given for testing not change anything besides my SSID & Password.
I am using Arduino 1.8.10 version, compiled on NodeMCU 1.0 board. All libraries also updated.
Please guide how to discover the device on Alexa or any other error if have any.
Please find below the program for reference

#include<weenyMo.h>

//
// This function will be called when Alexa hears "switch [on | off] 'vee three'"
// ESP8266 builtin LED is "backwards" i.e. active LOW, hence Alexa's ON=1 needs reversing
//
void onVoiceCommand(bool onoff){
Serial.printf("onVoiceCommand %d\n",onoff);
digitalWrite(BUILTIN_LED,!onoff);
}
//
bool getAlexaState(){ // We need this to let Alexa know if we are on or off
return !digitalRead(BUILTIN_LED); // Its "active low" so reverse it
}
// The only constructor: const char* name, function<void(bool)> onCommand
// choose the name wisely: Alexa has very selective hearing!
//
weenyMo w("vee three",onVoiceCommand);

void setup() {
Serial.begin(74880);
pinMode(BUILTIN_LED,OUTPUT);
digitalWrite(BUILTIN_LED,HIGH); // start OFF
WiFi.begin("","*"); // replace OF COURSE
WiFi.waitForConnectResult(); // so much neater than those stupid loops and dots
w.gotIPAddress(); // ready to roll...Tell Alexa to discover devices.
}

void loop() {}