WKWebView lädt keine https-URL?

Ich habe eine WKWebView, die folgende URL laden sollte: 

https://buchung.salonmeister.de/place/#offer-details-page?id=907599&venueId=301655

Ihr ist der Code, den ich verwende: 

import UIKit
import WebKit


class MMWKBrowserController: UIViewController {

  private let closeButtonSelector: Selector = "closeButtonTapped:"

  private var urlString: String
  private let request: NSMutableURLRequest

  private var webView: WKWebView!
  private var twoLineTitleView: UIView!
  private var titleLabel: UILabel?
  private var subTitleLabel: UILabel?
  private var indicator: UIActivityIndicatorView!


  init(urlString: String) {
    self.urlString = urlString

    println("*** Using MMWKBrowserController ***")

    var url: NSURL? = NSURL(string: urlString)
    if url == nil {
      var escapedString: String = urlString.stringByAddingPercentEscapesUsingEncoding(NSUTF8StringEncoding)!
      self.urlString = escapedString
      url = NSURL(string: escapedString)
    }

    println("url: \(url)")
    request = NSMutableURLRequest(URL: url!)

    request.setValue("Mozilla/5.0 (iPhone; CPU iPhone OS 8_4 like Mac OS X) AppleWebKit/600.1.4 (KHTML, like Gecko) Version/8.0 Mobile/12H141 Safari/600.1.4", forHTTPHeaderField: "UserAgent")

    super.init(nibName: nil, bundle: nil)
  }

  required init(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }


  deinit {
    self.webView.removeObserver(self, forKeyPath: "loading")
    self.webView.removeObserver(self, forKeyPath: "title")
    self.webView.removeObserver(self, forKeyPath: "URL")
    self.webView.removeObserver(self, forKeyPath: "estimatedProgress")
    self.webView.stopLoading()
  }


  override func viewDidLoad() {
    super.viewDidLoad()
    createNavigationView()


    self.navigationController?.navigationBar.tintColor = MGColor.actionColor

    let config = WKWebViewConfiguration()
    self.webView = WKWebView(frame: self.view.bounds, configuration: config)
    self.view.addSubview(self.webView)


    indicator = UIActivityIndicatorView(activityIndicatorStyle: UIActivityIndicatorViewStyle.Gray)
    //indicator.backgroundColor = UIColor(white: 0.1, alpha: 0.5)
    webView.addSubview(indicator)

    self.webView.snp_makeConstraints { (make) -> Void in
      make.edges.equalTo(self.view)
    }

    indicator.snp_makeConstraints { (make) -> Void in
      make.center.equalTo(self.webView)
    }

    webView.addObserver(self, forKeyPath: "loading", options: NSKeyValueObservingOptions.New, context: nil)
    webView.addObserver(self, forKeyPath: "title", options: NSKeyValueObservingOptions.New, context: nil)
    webView.addObserver(self, forKeyPath: "URL", options: NSKeyValueObservingOptions.New, context: nil)
    webView.addObserver(self, forKeyPath: "estimatedProgress", options: NSKeyValueObservingOptions.New, context: nil)
  }


  override func viewDidDisappear(animated: Bool) {
    super.viewDidDisappear(animated)
    self.webView.stopLoading()
  }


  private func createNavigationView() {
    let closeItem = UIBarButtonItem(barButtonSystemItem: UIBarButtonSystemItem.Stop, target: self, action: closeButtonSelector)
    self.navigationItem.leftBarButtonItem = closeItem

    // create center view
    let titleViewWidth = self.view.frame.size.width - 100

    twoLineTitleView = UIView(frame: CGRectMake(0, 0, titleViewWidth, 44))

    titleLabel = UILabel(frame: CGRectMake(0, 6, titleViewWidth, 16))
    titleLabel?.backgroundColor = UIColor.clearColor()
    titleLabel?.font = UIFont.boldSystemFontOfSize(16)
    titleLabel?.textAlignment = NSTextAlignment.Center

    subTitleLabel = UILabel(frame: CGRectMake(0, 21, titleViewWidth, 20))
    subTitleLabel?.backgroundColor = UIColor.clearColor()
    subTitleLabel?.font = UIFont.systemFontOfSize(10)
    subTitleLabel?.textAlignment = NSTextAlignment.Center

    twoLineTitleView.addSubview(titleLabel!)
    twoLineTitleView.addSubview(subTitleLabel!)
    self.navigationItem.titleView = twoLineTitleView
  }



  override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    self.webView.loadRequest(self.request)

  }


  func closeButtonTapped(sender: UIBarButtonItem) {
    self.presentingViewController?.dismissViewControllerAnimated(true, completion: nil)
  }


  override func observeValueForKeyPath(keyPath: String, ofObject object: AnyObject, change: [NSObject : AnyObject], context: UnsafeMutablePointer<Void>) {

    if let wk = object as? WKWebView {
      switch keyPath {
      case "loading":
        if let val: AnyObject = change[NSKeyValueChangeNewKey] {
          if let val = val as? Bool {
            if val {
              self.indicator.startAnimating()
            }
            else {
              self.indicator.stopAnimating()
            }
          }
        }
      case "title":
        self.titleLabel?.text = self.webView.title
      case "URL":
        self.subTitleLabel?.text = self.webView.URL?.URLString
      case "estimatedProgress":
        println("progress: \(Int32(self.webView.estimatedProgress*100))")

      default: break
      }
    }
  }


}

Hinweis: Ich verwende SDK iOS 8.4

Warum lädt mobile Safari diese URL, WKWebView jedoch nicht?