I am trying to implement PWA in standalone mode on Android and iOS. I have a secure node.js server (HTTPS) and everything is apparently working fine (index.html, manifest.js
I have solved the problem. A colleague told me that maybe the problem was due to the port configured on the server. I had configured the server node.js listening on a specific port (https://mydomain:xxxx), not in the default port (443), and this for some reason caused the PWA application not work in standalone mode on Android. I set up the server in the default port "443" and the PWA application already works correctly in standalone mode in both Android and iOS. Thanks to all.