Why can I not register for push notifications?

Swift version: 5.2

Paul Hudson @twostraws May 28th 2019

When you register for push notifications, one of two methods ought to be called: didRegisterForRemoteNotificationsWithDeviceToken is called when everything worked correctly, and didFailToRegisterForRemoteNotificationsWithError is called if something went wrong.

First, ensure you're correctly registering for push notifications, like this:

UNUserNotificationCenter.current().requestAuthorization(options: [.alert, .sound, .badge]) { granted, error in
    if let error = error {
        print("D'oh: \(error.localizedDescription)")
    } else {
        application.registerForRemoteNotifications()
    }
}

You should call that every time your app starts, because the user token can change, and the user can also adjust your app's permissions at any time.

Once you're sure you have registered for notifications, add these two methods to your app delegate:

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    print("Successfully registered for notifications!")
}

func application(_ application: UIApplication, didFailToRegisterForRemoteNotificationsWithError error: Error) {
    print("Failed to register for notifications: \(error.localizedDescription)")
}

Both of those just print out the status of your push request, which should give you an idea of what's going on. The most common reasons push notification request fail are: 1) you're using the iOS simulator, which does not support push notifications, and 2) your user has denied permission for push messages.