Broadcast Receiver is not working when application is removed from background?

I am trying to run this code in my mobile app, but it is not running and also giving no error. I have tried printing log also, but it is not showing anything in logcat. This problem only occur in Oreo and run well in all other Android versions, also runs well when application is in background.

public class MainActivity extends AppCompatActivity {

   AlarmManager am;
    TimeAlarm timeAlarm;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        am = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
        setOneTimeAlarm();
    }

    public void setOneTimeAlarm() {
        Intent intent = new Intent(this, TimeAlarm.class);

        PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, PendingIntent.FLAG_ONE_SHOT);

        am.set(AlarmManager.RTC_WAKEUP, System.currentTimeMillis() + (5 * 1000), pendingIntent);
    }

    public void setRepeatingAlarm() {
        Intent intent = new Intent(this, TimeAlarm.class);
        PendingIntent pendingIntent = PendingIntent.getBroadcast(this, 0, intent, PendingIntent.FLAG_CANCEL_CURRENT);
        am.setRepeating(AlarmManager.RTC_WAKEUP, System.currentTimeMillis(), (5 * 1000), pendingIntent);
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.d("ondestroy","ondestroy");

    }

    @Override
    protected void onStart() {
        super.onStart();
        Log.d("onstart","onstart");

        IntentFilter intentFilter=new IntentFilter("my.custom.action.tag.fordemo");
        intentFilter.addCategory(Intent.CATEGORY_DEFAULT);
        registerReceiver(timeAlarm,intentFilter);
    }
}

Code Of broadcast receiver, when I have removed the application from background it stopped working.

public class TimeAlarm extends BroadcastReceiver {

    NotificationManager nm;
    String channelId = "channel-01";
    String channelName = "Channel Name";
    int importance = NotificationManager.IMPORTANCE_HIGH;

    @RequiresApi(api = Build.VERSION_CODES.O)
    @Override
    public void onReceive(Context context, Intent intent) {
    nm = (NotificationManager) 
    context.getSystemService(Context.NOTIFICATION_SERVICE);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                NotificationChannel mChannel = new NotificationChannel(
                        channelId, channelName, importance);
                nm.createNotificationChannel(mChannel);
            } else {

            }
            CharSequence from = "Nithin";
            CharSequence message = "Crazy About Android...";
            PendingIntent contentIntent = 
            PendingIntent.getActivity(context, 0, new Intent(), 0);
            //Notification notif = new Notification(R.drawable.logo, 
           "Crazy About Android...", System.currentTimeMillis());
            NotificationCompat.Builder notification = new 
            NotificationCompat.Builder(context.getApplicationContext());
            // notification.setContentIntent(pintent);
       notification.setTicker(from).setSubText(from).setSmallIcon(R.drawable.logo);
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
                notification.setChannelId(channelId);
            }

            Notification notification1 = notification.build();
            notif.setLatestEventInfo(context, from, message,contentIntent);
            nm.notify(1, notification1);
        }
    }