Ionic 2 app works on Web but not Android

I’m doing an Ionic 2 app and everything looks good except one object not found.

I’m using a Beacon plugin of Cordova. It works before, but however after I ran ionic state reset --plugins, it just doesn’t work anymore. It throws an exception that Cannot read property 'Delegate' of undefined where I have var delegate: BeaconPlugin.Delegate = new this.locationManager.Delegate().

I tried to use ionic platform rm android and ionic platform add android as I did it before and it worked, but nothing get better this time.

Do anyone know how could I solve this weird problem?

We need more information. Maybe the plugin is not installed?

yes even with me…while using firebase for fb login .
it is working on browser(using ionic serve) but doesnt work on android.
I’ve installed whitelist plugin and added the meta tag in the index,html