ESP8266 Mailbox Notifier

#include <ESP8266WiFi.h>
#include <WiFiClientSecure.h>
#include <UniversalTelegramBot.h>

//edit BOTtoken, chat_id, message and wifi credentials
#define BOTtoken "0123456789:AAAAAAAbbbbbcccccddddddeeeeeeffffffgggg"
#define chat_id "9876543210"
#define message "You have mail!"
const char* ssid = "wifi-name";
const char* password = "wifi-password";

WiFiClientSecure client;
UniversalTelegramBot bot(BOTtoken, client);

void setup()
{
  client.setInsecure();
  int tries=0;
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

    //tries for 15sec to establish a wifi connection
  while (WiFi.status() != WL_CONNECTED && tries<15)
  {
    delay(1000);
    tries++;
  }

    //if there was no successful wifi connection after 15 seconds go to deep sleep
  if (tries==15)
  {
    ESP.deepSleep(0);
  }
}

void loop()
{
    //send message and go to deep sleep
  bot.sendMessage(chat_id, message, "");
  ESP.deepSleep(0);
}