Pending intent in notification not working

I added task builder and the below block code worked for me

Intent intent = new Intent(context, HomeActivity.class);
TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);
stackBuilder.addParentStack(SplashActivity.class);
stackBuilder.addNextIntent(intent);
PendingIntent pendingIntent = stackBuilder.getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT);

You might be using a notification id equal to 0. There is known issue with notification id being 0. If you will use any other id, it should work.

try this:

private void setNotification(String notificationMessage) {

//**add this line**
int requestID = (int) System.currentTimeMillis();

Uri alarmSound = getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
mNotificationManager  = getApplication().getSystemService(Context.NOTIFICATION_SERVICE);

Intent notificationIntent = new Intent(getApplicationContext(), NotificationActivity2.class);

//**add this line**
notificationIntent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP); 

//**edit this line to put requestID as requestCode**
PendingIntent contentIntent = PendingIntent.getActivity(this, requestID,notificationIntent, PendingIntent.FLAG_UPDATE_CURRENT);

NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(getApplicationContext())
.setSmallIcon(R.drawable.logo)
.setContentTitle("My Notification")
.setStyle(new NotificationCompat.BigTextStyle()
.bigText(notificationMessage))
.setContentText(notificationMessage).setAutoCancel(true);
mBuilder.setSound(alarmSound);
mBuilder.setContentIntent(contentIntent);
mNotificationManager.notify(NOTIFICATION_ID, mBuilder.build());

}