Code for Creating web server with ESP8266/NodeMCU

Create_web_server_with_ESP8266_NodeMCU.ino

#include <ESP8266WiFi.h>
#include <ESP8266WebServer.h>

ESP8266WebServer server(80);

const char* ssid = "WiFi_SSID"; //Enter Wi-Fi SSID
const char* password =  "WiFi_Password"; //Enter Wi-Fi Password
 
void setup() {
  Serial.begin(115200); //Begin Serial at 115200 Baud
  WiFi.begin(ssid, password);  //Connect to the WiFi network
  
  while (WiFi.status() != WL_CONNECTED) {  //Wait for connection
      delay(500);
      Serial.println("Waiting to connect...");
  }
  
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());  //Print the local IP
  
  server.on("/", handle_index); //Handle Index page
  
  server.begin(); //Start the server
  Serial.println("Server listening");
}

void loop() {
  server.handleClient(); //Handling of incoming client requests
}

void handle_index() {
  //Print Hello at opening homepage
  server.send(200, "text/plain", "Hello! This is an index page.");
}

Dear Sir,
Code is not working.
can you help me with this ?