Custom notification does not show in android

Question

I am trying to show a custom notification when I get a push notification from firebase, when the app is in background.

When the app is in background, the log messages START and END gets printed but does not show the notification on Android which I created as customNotification.

This is how I created a notification.

Could you please suggest what should be corrected please

    override fun onMessageReceived(message: RemoteMessage) {
        Log.d("FCMService", "onMessageReceived START")
        //super.onMessageReceived(message)
        // Get the layouts to use in the custom notification
        val notificationLayout = RemoteViews(packageName, R.layout.plugin_requires_approval_notification_small)
        val notificationLayoutExpanded = RemoteViews(packageName, R.layout.plugin_requires_approval_notification_large)

// Apply the layouts to the notification
        val customNotification = NotificationCompat.Builder(this, "FcmService")
            .setSmallIcon(R.mipmap.ic_launcher)
            .setStyle(NotificationCompat.DecoratedCustomViewStyle())
            .setCustomContentView(notificationLayout)
            .setCustomBigContentView(notificationLayoutExpanded)
            .build()

        val notificationManager = getSystemService(NOTIFICATION_SERVICE) as NotificationManager
        notificationManager.notify(0, customNotification)
        Log.d("FCMService", "onMessageReceived END")
    }

Thanks in advance R

EDIT it is fixed now, the issue was with the CHANNEL_ID I provided. for reference channelID should be the one used in the notificationChannel() function which looks like the bellow code, this is in the project App class.

 private fun createNotificationChannels() {
        // Do this only on API 26+ because the NotificationChannel
        // class is new and not in the AndroidX library
        if (SDK_INT >= O) {
            val caInfoNotifChannel = NotificationChannel(CaInfoProcessingService.NOTIFICATION_CHANNEL_ID,
                                                          getString(R.string.ca_info_service_notif_channel_name),
                                                          IMPORTANCE_LOW).apply {
                description = getString(R.string.ca_info_service_notif_channel_desc)
            }

            // Register the channel with the system
            getSystemService<NotificationManager>()?.createNotificationChannel(caInfoNotifChannel)
        }
    }