receive same notification every login

I’m creating a chat app where I receive notifications on my second device whenever I send a message. Each time I log in, I consistently receive the same notification.

this is my FirebaseNotificationService class

@SuppressLint("MissingFirebaseInstanceTokenRefresh")
public class FirebaseNotificationService extends FirebaseMessagingService {
    public static final String CHANNEL_ID_1 = "channel_1";
    public static final String CHANNEL_ID_2 = "channel_2";
    @SuppressLint("NewApi")
    @Override
    public void onMessageReceived(RemoteMessage remoteMessage) {
        String title = Objects.requireNonNull(remoteMessage.getNotification()).getTitle();
        String text = Objects.requireNonNull(remoteMessage.getNotification()).getBody();
        assert title != null;
        if (title.contains("chat")) {
            PendingIntent contentIntent = PendingIntent.getActivity(
                    this,
                    255,
                    new Intent(this, SplashActivity.class), PendingIntent.FLAG_UPDATE_CURRENT);
            AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
            alarmManager.cancel(contentIntent);
            NotificationChannel channel_chat = new NotificationChannel(
                    CHANNEL_ID_2,
                    "Message Notification",
                    NotificationManager.IMPORTANCE_HIGH);
            getSystemService(NotificationManager.class).createNotificationChannel(channel_chat);
            Notification.Builder notification_chat = new Notification.Builder(this, CHANNEL_ID_2)
                    .setContentTitle(title)
                    .setContentText(text)
                    .setSmallIcon(R.drawable.logo)
                    .setContentIntent(contentIntent)
                    .setPriority(Notification.PRIORITY_DEFAULT)
                    .setAutoCancel(true);
            NotificationManager manager = getSystemService(NotificationManager.class);
            NotificationManagerCompat.from(this).notify(255, notification_chat.build());
            if (manager != null) {
                manager.notify(255, notification_chat.build());
            }
        } else {
            PendingIntent contentIntent = PendingIntent.getActivity(
                    this,
                    255,
                    new Intent(this, SplashActivity.class), PendingIntent.FLAG_UPDATE_CURRENT);
            AlarmManager alarmManager = (AlarmManager) getSystemService(ALARM_SERVICE);
            alarmManager.cancel(contentIntent);
            NotificationChannel channel = new NotificationChannel(
                    CHANNEL_ID_1,
                    "Message Notification",
                    NotificationManager.IMPORTANCE_HIGH);
            getSystemService(NotificationManager.class).createNotificationChannel(channel);
            Notification.Builder notification = new Notification.Builder(this, CHANNEL_ID_1)
                    .setContentTitle(title)
                    .setContentText(text)
                    .setSmallIcon(R.drawable.logo)
                    .setContentIntent(contentIntent)
                    .setPriority(Notification.PRIORITY_DEFAULT)
                    .setAutoCancel(true);
            NotificationManager manager = getSystemService(NotificationManager.class);
            NotificationManagerCompat.from(this).notify(255, notification.build());
            if (manager != null) {
                manager.notify(255, notification.build());
            }
        }
        super.onMessageReceived(remoteMessage);
    }
    private void broadcastNewNotification() {
        Intent intent = new Intent(NEW_NOTI);
        LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
    }
    public static final String NEW_NOTI = "new_notification";
}

How can I make the notifications come only once?