Didn't play video with AVPLayer

I use AVPlayer for playing video from URL. Below code that I use:

@implementation VideoPlayerController  {
    IBOutlet UIWebView* webView;
}

-(void)viewDidLoad {
    [super viewDidLoad];

    self.navigationController.navigationBar.tintColor = [UIColor whiteColor];

    NSString* urlString = [NSString stringWithFormat:@"%@", self.videoUrl];
    NSURL *videoURL = [NSURL URLWithString:urlString];
    [self startPlaybackForItemWithURL:videoURL];

}

-(void)startPlaybackForItemWithURL:(NSURL*)url {

    // First create an AVPlayer
    AVPlayer *player = [AVPlayer playerWithURL:url];
    self.player = player;
    // Begin playback
    [player play];

}

- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:YES];

    [[UIDevice currentDevice] setValue:
     [NSNumber numberWithInteger: UIInterfaceOrientationPortrait]
                                forKey:@"orientation"];
    [self.player pause];

}

@end

So on iOS 12 device video loading very long time, but after this is playing... But on some devices (on iOS 11.4, iPhone 7 32 Gb) there are some error:

Task <7813A625-BBCF-4486-BC48-D6B066129F41>.<2> finished with error - code: -999
Task <37ED66A3-0404-414D-969E-CB5E118BDE4B>.<1> finished with error - code: -999
TIC Read Status [40:0x0]: 1:57
Task <37ED66A3-0404-414D-969E-CB5E118BDE4B>.<1> HTTP load failed (error code: 12 [1:12])

The example of video from media server that I must use to playing videos is here

I need help mb with code, or mb the video is bad for playing.

Thanks!