Iframe embedding webapp


Currently, I am trying to create a mobile app to embed my web app.
I am using an iframe to load the website and it seems to be fine. However, the webapp has some links to download files and when I click over them, nothing happens, I mean file is nor opened neither downloaded to the android device.

Does anyone know what should I do?

I already added these permissions in the manifest file

uses-permission android:name=“android.permission.INTERNET” />
uses-permission android:name=“android.permission.ACCESS_NETWORK_STATE” />
uses-permission android:name=“android.permission.READ_EXTERNAL_STORAGE” />
uses-permission android:name=“android.permission.WRITE_EXTERNAL_STORAGE” />
uses-permission android:name=“android.permission.ACCESS_DOWNLOAD_MANAGER” />