Chrome's built-in banner does not work

Question

Chrome's built-in banner does not work

I am trying to turn on the display of the built-in application installation banner for my client site using the documentation https://developers.google.com/web/updates/2015/03/increasing-engagement-with-app-install-banners-in-chrome-for -android .

I see a mistake App banner not shown: manifest could not be fetched, is empty, or could not be parsed

Below mine manifest.json

{
  "name": "PayPal",
  "short_name": "PayPal",
  "start_url": "https://www.paypal.com/webapps/mpp/home",
  "display": "standalone",
  "icons": [{
    "src": "https://www.paypalobjects.com/digitalassets/c/website/logo/monogram/pp_fc_mg.png",
    "sizes": "48x48",
    "type": "image/png"
  }, {
    "src": "https://www.paypalobjects.com/digitalassets/c/website/logo/monogram/pp_fc_mg_2x.png",
    "sizes": "96x96",
    "type": "image/png"
  }, {
    "src": "https://www.paypalobjects.com/digitalassets/c/website/logo/monogram/pp_fc_mg_2x.png",
    "sizes": "144x144",
    "type": "image/png"
  }],
  "prefer_related_applications": true,
  "related_applications": [{
    "platform": "play",
    "id": "com.paypal.android.p2pmobile"
  }]
}