Android mobile app's in-app update is not working

Question

I have implemented in-app update code to my android mobile app to check if any upgraded version is available with the google play store and notify if any and then download it. But it is not at all working.

My code(MainActivity.java) is, as follow:-

import android.content.Intent;
import android.content.IntentSender;
import android.os.Bundle;
import android.view.MenuItem;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import com.google.android.material.bottomnavigation.BottomNavigationView;
import com.google.android.material.snackbar.Snackbar;
import com.google.android.play.core.appupdate.AppUpdateInfo;
import com.google.android.play.core.appupdate.AppUpdateManager;
import com.google.android.play.core.appupdate.AppUpdateManagerFactory;
import com.google.android.play.core.install.InstallStateUpdatedListener;
import com.google.android.play.core.install.model.AppUpdateType;
import com.google.android.play.core.install.model.InstallStatus;
import com.google.android.play.core.install.model.UpdateAvailability;
import com.google.android.play.core.tasks.Task;


import java.io.*;
import androidx.appcompat.app.AppCompatActivity;
import androidx.annotation.NonNull;
import com.google.android.material.bottomnavigation.BottomNavigationView;


import android.os.Bundle;
import android.view.MenuItem;


public class MainActivity extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener {

   
    private AppUpdateManager appUpdateManager;
    private static final int IMMEDIATE_APP_UPDATE_REQ_CODE = 124;



    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

   

        appUpdateManager = AppUpdateManagerFactory.create(getApplicationContext());
        checkUpdate();
    }


   
   

    private void checkUpdate() {

        Task<AppUpdateInfo> appUpdateInfoTask = appUpdateManager.getAppUpdateInfo();

        appUpdateInfoTask.addOnSuccessListener(appUpdateInfo -> {
            if (appUpdateInfo.updateAvailability() == UpdateAvailability.UPDATE_AVAILABLE
                    && appUpdateInfo.isUpdateTypeAllowed(AppUpdateType.IMMEDIATE)) {
                startUpdateFlow(appUpdateInfo);
            } else if  (appUpdateInfo.updateAvailability() == UpdateAvailability.DEVELOPER_TRIGGERED_UPDATE_IN_PROGRESS){
                startUpdateFlow(appUpdateInfo);
            }
        });
    }

    private void startUpdateFlow(AppUpdateInfo appUpdateInfo) {
        try {
            appUpdateManager.startUpdateFlowForResult(appUpdateInfo, AppUpdateType.IMMEDIATE, this, MainActivity.IMMEDIATE_APP_UPDATE_REQ_CODE);
        } catch (IntentSender.SendIntentException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == IMMEDIATE_APP_UPDATE_REQ_CODE) {
            if (resultCode == RESULT_CANCELED) {
                Toast.makeText(getApplicationContext(), "Update canceled by user! Result Code: " + resultCode, Toast.LENGTH_LONG).show();
            } else if (resultCode == RESULT_OK) {
                Toast.makeText(getApplicationContext(), "Update success! Result Code: " + resultCode, Toast.LENGTH_LONG).show();
            } else {
                Toast.makeText(getApplicationContext(), "Update Failed! Result Code: " + resultCode, Toast.LENGTH_LONG).show();
                checkUpdate();
            }
        }
    }

   }

I have also put implementation 'com.google.android.play:core:1.10.3' in the dependencies of build.gradle(:app)

Please let me know where the issue is and oblige me thereby.

Thanks.