Why is my app not responding to remote control events?

Question

I'm making an app that plays an audio stream on the background when the device is locked. I want the app to respond to the media controls on the lock screen. I followed this answer but for some reason I can't make my app respond to these controls. This is the code I have on my View Controller

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    UIApplication.shared.beginReceivingRemoteControlEvents()
    becomeFirstResponder()
}

override var canBecomeFirstResponder: Bool {
    return true
}

override func remoteControlReceived(with event: UIEvent?) {
    guard let event = event else { return }
    if event.type == .remoteControl {
        switch event.subtype {
        case .remoteControlTogglePlayPause:
            if player.rate == 0 {
                player.pause()
            } else {
                player.play()
            }
        case .remoteControlPlay:
            player.play()
            break

        case .remoteControlPause:
            player.pause()
            break

        default:
            break
        }
    }
}`

Any guidance on what I'm doing wrong will be really appreciated!