amp app banner does not show in android and IOS device working fine

I am using following code below which is not showing AMP app banner.

Here is the example.

<script async custom-element="amp-app-banner" src="https://cdn.ampproject.org/v0/amp-app-banner-0.1.js"></script>
<meta name="apple-itunes-app" content="app-id=828256236, app-argument=medium://p/9ea61abf530f">
<link rel="manifest" href="/amp-app-banner-manifest.json">

{
  "prefer_related_applications": true,
  "related_applications": [
    {
      "platform": "play",
      "id": "com.medium.reader",
      "url": "android-app://com.medium.reader/https/medium.com/p/cb7f223fad86"
    }
  ]
}