No webpage displayed ESP8266

I am flashing the code which is mentioned below to the NODEMCU. It get configured as SoftAP and I am able to login but when I try to connect to it from browser it does not show any webpage. Am I missing anything? Please Help.

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



IPAddress local_IP(192,168,4,2);
IPAddress gateway(192,168,4,1);
IPAddress subnet(255,255,255,0);

ESP8266WebServer server(80);

int led = 13;
const char* ssid = "NODEMCU_";
const char* pass = "12345678";
const int wifi_Channel = 9;
String webpage;


void setup() 
{

  Serial.begin(9600);
  pinMode(led, OUTPUT);
  digitalWrite(led, HIGH);
   
  String finalString, mac;
  const char* ssid_1;

  mac = WiFi.softAPmacAddress().c_str();
  finalString = ssid + mac;
  ssid_1 = finalString.c_str();

  Serial.print("configuring soft-AP configuration ...");
  Serial.println(WiFi.softAPConfig(local_IP, gateway, subnet)? "Ready" : "Failed!");

  Serial.print("setting soft-ap ...");
  Serial.println(WiFi.softAP(ssid_1, pass, wifi_Channel) ? "Ready" : "Failed!");

  Serial.println();
  Serial.print("MAC address:-");
  Serial.println(mac);
  Serial.print("ssid:- ");
  Serial.print(ssid_1);
  Serial.println();
  Serial.print("password:- ");
  Serial.print(pass);
  Serial.println();
  Serial.print("Soft-AP IP address = ");
  Serial.println(WiFi.softAPIP());



            webpage += String("HTTP/1.1 200 OK\r\n")+
                       "Content-Type: text/html\r\n"+
                       "Connection: close\r\n"+
                       "<!DOCTYPE HTML>"+
                       "<html>"+
                       "<head>"+
                       "<title> EMERGENCY MODE </title>"+
                       "</head>"+
                       "<body>"+
                       "<p> <a href=\"socket1\"><button> UNLOCK </button></a></p>"+
                       "</body>"+
                       "</html>"+
                       "\r\n";


  server.on("/", [](){
    server.send(200, "text/html", webpage);
  });
  
  server.on("/socket1", []()
    {
    server.send(200, "text/html", webpage);
    digitalWrite(led, LOW);
    delay(1000);
    digitalWrite(led, HIGH);
  }
  );
}

void loop() 
{
  server.handleClient();
}

Thank you.