Some Oreo devices are not getting Push Notification

Question

Samsung S8/S5/J2/Note3 are getting Firebase Push Notification successfully either app is killed, in background or foreground,

but In

Answer 1

Since oreo there is new Notification Channels implementation (started in Android 8.0 (API level 26))

so you have to create the channel using below code

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
            CharSequence name = "News Channel";
            String description = "Default Notification News Channel";
            int importance = NotificationManager.IMPORTANCE_DEFAULT;
            NotificationChannel channel = new NotificationChannel(CHANNEL_ID, name, importance);
            channel.setDescription(description);
            NotificationManager notificationManager = getAppContext().getSystemService(NotificationManager.class);
            notificationManager.createNotificationChannel(channel);
        }

and override notification builder as below

NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(getAppContext(),CHANNEL_ID);

assuming you have CHANNEL_ID value something you want

String CHANNEL_ID = "DEFAULT_NEWS_CHANNEL";

this is already tested with OnePlus3T device so it should work for you