AVAudioPlayer prepareToPlay() return false

I have 2 apps for audio playback, I need to check a case when the first app was interrupted the sound should stops to play, however, when the interruption is end the app should return to playback.

There is a great example with exact implementation of it - https://stackoverflow.com/a/71678102/5709159

The trick is when the interruption app finished its playback this event has to be fired:

try? AVAudioSession.sharedInstance().setActive(false, options: .notifyOthersOnDeactivation)

and the first app (one should continue to play) has to catch this event like this

self.observer = NotificationCenter.default.addObserver(forName:
            AVAudioSession.interruptionNotification, object: nil, queue: nil) {
                [weak self] n in
                guard let self = self else { return } // legal in Swift 4.2
                let why = n.userInfo![AVAudioSessionInterruptionTypeKey] as! UInt
                let type = AVAudioSession.InterruptionType(rawValue: why)!
                switch type {
                case .began:
                    print("interruption began:\n\(n.userInfo!)")
                case .ended:
                    print("interruption ended:\n\(n.userInfo!)")
                    guard let opt = n.userInfo![AVAudioSessionInterruptionOptionKey] as? UInt else {return}
                    let opts = AVAudioSession.InterruptionOptions(rawValue: opt)
                    if opts.contains(.shouldResume) {
                        print("should resume")
                        print("Is playing: \(self.player.isPlaying)")
                        print("is I prepared to play: \(self.player.prepareToPlay())")
                        print("bp tried to resume play: did I? \(self.player.play())")
                    } else {
                        print("not should resume")
                    }
                @unknown default: fatalError()
                }
        }

The problem is that this line - self.player.prepareToPlay() returns false

What am I missing here?