App with Firebase not working on Android device but fine in browser

When I run my app which uses Firebase, it runs fine on the browser. However when testing it on an Android device it does not work.
I get a 404 error when trying to load
I have no idea why this is happening. Can anyone help, please? Thanks!

This is a whitelisting problem. The remote assets (the JS) is blocked by the security constraints. Read up on the whitelist plugin and how to configure and you will be good to go.