流视频Swift Xcode10

I am trying to stream a video from my server. It working in Android and also in iOS, if I download it and put in app's bundle. But not able to stream through URL. I have tried other URL for streaming, and all are working. Below is the code I am using.

      //its working
      //let str = "https://www.radiantmediaplayer.com/media/bbb-360p.mp4"

      //not able to stream from this url
      let str = "http://158.69.119.121:5555/uploads/post_images/dyqZzJprVCgUxX676ELQTbmEk32EjzBIqrbqhKyr2Sk9fATIa9.mp4"

        if let url = URL(string: str){

            let player = AVPlayer(url: url)
            let playervc = AVPlayerViewController()
            playervc.player = player
            self.present(playervc, animated: true) {
                playervc.player!.play()
            }
        }