Notifications not being delivered

So my application is using the Parse platform to send notifications to different devices and to ensure that the device receives the notification I've added an expiration time to it.

This works sometimes whenever the device is in airplane mode but it almost never works whenever I switch the device off and turn it back on the notification doesn't get delivered to the device. Below are the steps I take to test this:

• Put phone in airplane mode for more than 5 minutes and connect back to wifi: Sometimes the notification is delivered or it's delivered with a delay with no sound or vibrations.
• Switch the phone off completely for more than 5 minutes and turn it back on: The notification is never delivered.

Like I mentioned I'm using the Parse SDK and I'm mainly using the cloud code which is written in JS to get the time 4 hours from now and create a date object from this since this is what is required for the expiration_time parameter.

Here is the code I'm using to get the time 4 hours from now.

    // Expiration date
    var now = new Date();
    var futureTime = now.setHours(now.getHours() + 4);
    var expireDate = new Date(futureTime);

Then I'm using an object to create my own payload since I want to use rich notifications within my iPhone application. Below is the structure of the JS object of the payload, note the expireDate used from above.

    // Get the device from installations
    var pushQuery = new Parse.Query(Parse.Installation);
    pushQuery.equalTo("deviceToken", withToken);

    // APNS Payload
    var payload = {
        where: pushQuery,
        expiration_time: expireDate,
        data: {
            sound : "Wakeup.wav",
            aps: {
                alert: {
                    title : "Good morning!",
                    subtitle: "Today's forcast in " + withCity,
                    body: withSummary
                },
               "content-available":1,
               "mutable-content" : 1,
               icon: withIcon
            }
        }
    };

Then this is just sent using the standard Parse push function as you can see below.

    Parse.Push.send(payload,{ useMasterKey: true,
        success: function() {
            response.success("Successful push, future time: " + futureTime + " Date object: " + new Date(futureTime));
        },
        error: function(error) {
            response.error("Failed");
        }

    });

I was just wondering if anyone could give any insight into why this may be happening at all? I don't know if this will help but the device I'm using is and it's current status is:

• Device: iPhone 5
• OS: iOS 10.2
• Battery level: 49%