wifi_fast_connection.ino

const char *wifiSSID = "MY_WIFI";      
const char *wifiPassword = "MY_PASS";
#define MQTT_HOST "mybroker"
#deinfe MQTT_PORT 1883

#include <ESP8266WiFi.h>
WiFiClient wifiClient;
#include <AsyncMqttClient.h>

AsyncMqttClient mqttClient;
void onMqttConnect(bool sessionPresent) {
    Serial.print(millis());
    Serial.println(" Connected to MQTT.");
}

void setup()
{
  Serial.begin(115200);
  WiFi.config(IPAddress(192,168,1,11), IPAddress(192,168,1,1), IPAddress(255, 255, 255, 0));
  uint8_t bssid[] = {0xEE, 0x59, 0x65, 0x25, 0xC9, 0xE3};
  uint8_t channel = 1;

  Serial.println(F("Initialising Wifi..."));
  WiFi.mode(WIFI_STA);
  WiFi.begin(wifiSSID, wifiPassword,channel, bssid,true);
  WiFi.persistent(true);
  WiFi.setAutoConnect(true);
  WiFi.setAutoReconnect(true);

  if (WiFi.waitForConnectResult() != WL_CONNECTED)
  {
    Serial.println(F("Connection Failed!")); //##################  IT is not called. 
    // Change settings now. 
    WiFi.disconnect();
    WiFi.begin(wifiSSID, wifiPassword);
    WiFi.persistent(true);
    WiFi.setAutoConnect(true);
    WiFi.setAutoReconnect(true);
     if (WiFi.waitForConnectResult() != WL_CONNECTED){
      Serial.println(F("Connection Failed Again!"));
     }
  }
  Serial.println(millis());
  Serial.println(WiFi.localIP().toString());
  Serial.println(WiFi.macAddress());
  Serial.println(WiFi.gatewayIP().toString());
  Serial.println(WiFi.dnsIP().toString());
  Serial.println(WiFi.subnetMask().toString());
  Serial.println(WiFi.channel());
  Serial.println(WiFi.BSSIDstr());
  
  mqttClient.onConnect(onMqttConnect);
  mqttClient.setServer(MQTT_HOST, MQTT_PORT);
  mqttClient.setCredentials("MY_USER_ID", "MY_PASS");


  mqttClient.connect();
}

void loop()
{
  delay(10000);
  ESP.restart();
}