ESP8266 is not getting connected to my deployed websocket on heroku - node.js

Question

I have deployed a nodejs websocket on heroku. But my ESP8266 cannot get connected to that websocket. Before deploying that websocket on heroku, i tried it out locally and it worked pretty well. ESP8266 also got connected to it without any error. Then I made some changes in nodejs socket (before deploying) in order to run it on heroku. i just don't understand what's wrong with this esp8266 code
ESP8266's Code
#include <ESP8266WiFi.h>
#include <WebSocketClient.h>
boolean handshakeFailed = 0;
String data = "";
char path[] = "/"; //identifier of this device
const char *ssid = ""; //<-------------------this was entered correctly. Wifi connection was successful. websocket connection got failed
const char *password = ""; // <-------------------this was entered correctly. Wifi connection was successful. websocket connection got failed
char *host = "example.herokuapp.com"; //replace this ip address with the ip address of your Node.Js server
const int espport = 3000;
WebSocketClient webSocketClient;
unsigned long previousMillis = 0;
unsigned long currentMillis;
unsigned long interval = 300; //interval for sending data to the websocket server in ms
// Use WiFiClient class to create TCP connections
WiFiClient client;
void setup()
{
Serial.begin(115200);
pinMode(LED_BUILTIN, OUTPUT); // Initialize the LED_BUILTIN pin as an output
delay(10);
// We start by connecting to a WiFi network
Serial.println();
Serial.println();
Serial.print("Connecting to ");
Serial.println(ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
delay(1000);
wsconnect();
// wifi_set_sleep_type(LIGHT_SLEEP_T);
}
void loop()
{
if (client.connected())
{
currentMillis = millis();
webSocketClient.getData(data);
if (data.length() > 0)
{
Serial.println(data);
//*************send log data to server in certain interval************************************
//currentMillis=millis();
if (abs(currentMillis - previousMillis) >= interval)
{
previousMillis = currentMillis;
data = (String)analogRead(A0); //read adc values, this will give random value, since no sensor is connected.
//For this project we are pretending that these random values are sensor values
webSocketClient.sendData(data); //send sensor data to websocket server
}
}
else
{
}
delay(5);
}
}
void wsconnect()
{
// Connect to the websocket server
if (client.connect(host, espport))
{
Serial.println("WebSocket Connected");
}
else
{
Serial.println("Connection failed.");
delay(1000);
if (handshakeFailed)
{
handshakeFailed = 0;
ESP.restart();
}
handshakeFailed = 1;
}
// Handshake with the server
webSocketClient.path = path;
webSocketClient.host = host;
if (webSocketClient.handshake(client))
{
Serial.println("Handshake successful");
}
else
{
Serial.println("Handshake failed.");
delay(4000);
if (handshakeFailed)
{
handshakeFailed = 0;
ESP.restart();
}
handshakeFailed = 1;
}
}