Communication Between NodeMcu and Wifi Terminal(android app)

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1

Hi guys!
I'm working on communicating to a NodeMcu in Access Point mode with my phone .
my code recognizes that my phone is connected to nodemcu and shows it's ip and mac address in serial terminal ,
But when i want to connect to nodemcu's ip with my Wifi Terminal app it just doesn't connect and says "client disconnected : Socket closed !"

Please Help me ... :sob:

note that this communication works when i use nodemcu in Station mode and connect it to another Access Point .

This is my code( The Actual function of this code is to first start as AP and get the SSID and PASSWORD of a router from an WIfi terminal and then with that information connect to the specified router ! ) :

#include <ESP8266WiFi.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
extern "C" {
#include "user_interface.h"
}

char ssid[31] = "NodeMcu";
char password[63] = "227485300";
byte mac[6];
bool first=1 ;
boolean waitingDHCP=false;
char last_mac[18];   
WiFiServer server(1337); // set port

void printWiFiStatus();

// Manage incoming device connection on ESP access point
void onNewStation(WiFiEventSoftAPModeStationConnected sta_info) {
  Serial.println("New Station :");
  sprintf(last_mac,"%02X:%02X:%02X:%02X:%02X:%02X", MAC2STR(sta_info.mac));
  Serial.printf("MAC address : %s\n",last_mac);
  Serial.printf("Id : %d\n", sta_info.aid);
  waitingDHCP=true;
}
void setup(void) {
  static WiFiEventHandler e1;
  Serial.begin(9600);
  if(first)
  {
   //WiFi.softAP(ssid, password);
   WiFi.mode(WIFI_AP_STA);
   IPAddress myIP = WiFi.softAP(ssid,password);
   //IPAddress myIP = WiFi.softAPIP();
   Serial.print("AP IP address: ");
   Serial.println(myIP);
   // Event subscription
   e1 = WiFi.onSoftAPModeStationConnected(onNewStation);
  }
  
  // Configure GPIO2 as OUTPUT.
  pinMode(LED_BUILTIN, OUTPUT);
                
  // Start TCP server.
  server.begin();
  //server.begin();
}

void loop(void) 
{
  bool WifiConnected = false , ClientConnected = false ;
  // Check if module is still connected to WiFi.
  if(first==0)
  {
  if (WiFi.status() != WL_CONNECTED) {
    while (WiFi.status() != WL_CONNECTED) {
      delay(500);
    }
    WifiConnected = true ;
    // Print the new IP to Serial.
    printWiFiStatus();
   }
  }
  else
  {
    if (waitingDHCP)
   {
    String cb;
    if (deviceIP(last_mac,cb))
    {
      Serial.println("Ip address :");
      Serial.println(cb); //do something
      WifiConnected = true ;
    } 
    else
    {
      Serial.println("Problem during ip address request :");
      Serial.println(cb); //do something else
    }
   }
   delay(2000);
  }
 WiFiClient client = server.available();
 if(WifiConnected == true)
 { 
  if (client) {
    Serial.println("Client connected.");

    while (client.connected()) {
      ClientConnected = true ;
      if (client.available()) {
        String data ;
        
        char str[100], i=0 ;

        for(char j=0 ;j<20;j++)
        {
          str[j]='\0' ;
        }
        i = 0 ;
        do
        {  
         if (client.available()) 
         {
          str[i] = client.read();
          i++ ;
         }
         if(i==100)break ;
        }
        while(str[i-1]!='!');
        Serial.println("! Found ") ;
        Serial.println(str) ;
        if (!strcmp(str,"LED_ON!")) 
        {
          digitalWrite(LED_BUILTIN, LOW);
          Serial.println("Lamp is now on.");
        }
        if (!strcmp(str,"LED_OFF!")) 
        {
          digitalWrite(LED_BUILTIN, HIGH);
          Serial.println("Lamp is now off.");
        }
        if (str[0]=='H') 
        {
          unsigned char h ;
          first=0 ;
          Serial.println("Recieving new SSID & Password ...");
          i=1 ;
          while(str[i]!=':')
          {  
           ssid[i-1] = str[i] ;
           i++ ;
           if(i==33)break ;
          }
          i++ ;
          h=i ;
          while(str[i]!='!')
          {  
           password[i-h] = str[i] ;
           i++ ;
           if(i==65)break ;
          }
          client.stop();
          Serial.println("Client disconnected.");
          WiFi.disconnect() ;
          WiFi.mode(WIFI_STA);
          Serial.println("Access Point Terminated!");
          WiFi.begin(ssid, password);
          Serial.println("Connecting to new SSID ...");
          server.begin();
        }
          
        }
      }
    }
  } 
  if(ClientConnected == true)
  {
   Serial.println("Client disconnected.");
   client.stop();
  }
}

void printWiFiStatus() {
  Serial.println("");
  Serial.print("Connected to ");
  Serial.println(ssid);
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());
      WiFi.macAddress(mac);
    Serial.print("MAC: ");
    Serial.print(mac[5],HEX);
    Serial.print(":");
    Serial.print(mac[4],HEX);
    Serial.print(":");
    Serial.print(mac[3],HEX);
    Serial.print(":");
    Serial.print(mac[2],HEX);
    Serial.print(":");
    Serial.print(mac[1],HEX);
    Serial.print(":");
    Serial.print(mac[0],HEX);
    Serial.println("Signal strength : ") ;
    Serial.print(WiFi.RSSI()+"dBm") ;
}

boolean deviceIP(char* mac_device, String &cb) {

  struct station_info *station_list = wifi_softap_get_station_info();

  while (station_list != NULL) {
    char station_mac[18] = {0}; sprintf(station_mac, "%02X:%02X:%02X:%02X:%02X:%02X", MAC2STR(station_list->bssid));
    String station_ip = IPAddress((&station_list->ip)->addr).toString();

    if (strcmp(mac_device,station_mac)==0) {
      waitingDHCP=false;
      cb = station_ip;
      return true;
    } 

    station_list = STAILQ_NEXT(station_list, next);
  }

  wifi_softap_free_station_info();
  cb = "DHCP not ready or bad MAC address";
  return false;
}