Local Notifications not working as expected

I’m trying to implement Local Notifications in Ionic 2, but it doesn’t seem to work properly. This is the code I’m using:

    onPageWillEnter() {

            .subscribe(data => {
                this.notificationTime = data;
                var time = new Date();

                    id: 1,
                    title: "Title",
                    text: "Lorem ipsum",
                    firstAt: time,
                    every: "day",
                    led: "ff5454",
                    sound: 'notification.mp3',
                    icon: "img/notification.png",

So this retrieves a time for the notification to appear from an API. The notification doesn’t show up when my phone is locked. The LED, sound and icon are also not working. Am I missing something? I’m testing on Android 6 in case that matters. The notification.mp3 and img/notification.png are in the www folder.