ESP8266 stopped receiving data from firebase - firebase

Question

I am trying to receive data from firebase to my ESP8266 so that I can send a mail using received data on button press. But the ESP stops receiving data after a couple of minutes. Can anyone tell the reason behind it?
Here's the code.
#include <ESP8266WiFi.h>
#include "Gsender.h"
#include <FirebaseArduino.h>
#define FIREBASE_HOST "iotapp11.firebaseio.com"
int button = 0;
const char* ssid = "Redmi 3s";
const char* password = "alohomora";
void setup()
{
pinMode(button,INPUT);
Serial.begin(115200);
Serial.printf("Connecting to %s ", ssid);
WiFi.begin(ssid, password);
while (WiFi.status() != WL_CONNECTED)
{
delay(500);
Serial.print(".");}
Serial.println(" connected");
Serial.println(WiFi.localIP());
Firebase.begin(FIREBASE_HOST);
}
void loop(){
Firebase.get(FIREBASE_HOST); //Tried putting it in void setup and even removed it but nothing worked.
int but_val = digitalRead(button);
Gsender *gsender = Gsender::Instance();
String emailid =Firebase.getString("Email");
String subject =Firebase.getString("Subject");
String content =Firebase.getString("Content");
Serial.println(emailid);
Serial.println(subject);
Serial.println(content);
if ( but_val == LOW){
Serial.println("Button pressed");
delay(1000);
gsender->Subject(subject)->Send(emailid, content) ;
Serial.println("Message sent.");
delay(1000);
} else {
Serial.println("Button Not pressed");
delay(1000);
}
}