Install in-house application when the iPhone is in Single app mode

My in-house application is hosted in my website. I'd like to download and install it inside my application. Here is my code:

@IBOutlet weak var webView: UIWebView!
  override func viewDidLoad() {
    super.viewDidLoad()
    self.webView.delegate = self

    let htmlFile = Bundle.main.path(forResource: "install", ofType: "html")
    let html = try? String(contentsOfFile: htmlFile!, encoding: String.Encoding.utf8)
    webView.loadHTMLString(html!, baseURL: nil)
  }

The link to ipa in install.html:

<div class="section hero">

<div class="container">

<div class="row">

<div class="one-half column">

<h5 class="">Enterprise In-House App distribution.</h6>

<a class="button button-primary" href="itms-services://?action=download-manifest&url=https://myweb.com.com/ipa/manifest.plist">Download Your App</a>

</div>

</div>

</div>

</div>

A popup comes out to ask for installation when I click the Download Your App link. After click the Install, The application will be installed without problem. But when I set the device to Single App Mode or Guided Access Mode, the popup won't be shown so that the application won't be installed.

Any idea to overcome this problem? Thanks.