Can't resolve all parameters for Auth: (?) error, ionic2 AngularJS - angularjs

Question

i wanted to provide authonification to my ionic2 app, so i followed the official documentation and applied it to a brand new ionic2 app ionic start my_app blank
once i serve my app, this error fires :
Error: Can't resolve all parameters for Auth: (?).
at syntaxError (http://localhost:8100/build/main.js:107898:34)
at CompileMetadataResolver._getDependenciesMetadata (http://localhost:8100/build/main.js:121235:35)
at CompileMetadataResolver._getTypeMetadata (http://localhost:8100/build/main.js:121103:26)
at CompileMetadataResolver._getInjectableMetadata (http://localhost:8100/build/main.js:121089:21)
at CompileMetadataResolver.getProviderMetadata (http://localhost:8100/build/main.js:121379:40)
at http://localhost:8100/build/main.js:121308:49
at Array.forEach (<anonymous>)
at CompileMetadataResolver._getProvidersMetadata (http://localhost:8100/build/main.js:121269:19)
at CompileMetadataResolver.getNgModuleMetadata (http://localhost:8100/build/main.js:120924:50)
at JitCompiler._loadModules (http://localhost:8100/build/main.js:131988:66)
i've injected Auth with providers in app.moodule.ts as you can
import { BrowserModule } from '#angular/platform-browser';
import { ErrorHandler, NgModule } from '#angular/core';
import { IonicApp, IonicErrorHandler, IonicModule } from 'ionic-angular';
import { SplashScreen } from '#ionic-native/splash-screen';
import { StatusBar } from '#ionic-native/status-bar';
import { MyApp } from './app.component';
import { Auth } from '#ionic/cloud-angular';
#NgModule({
declarations: [
MyApp,
],
imports: [
BrowserModule,
IonicModule.forRoot(MyApp)
],
bootstrap: [IonicApp],
entryComponents: [
MyApp,
],
providers: [
StatusBar,
SplashScreen,
Auth,
{provide: ErrorHandler, useClass: IonicErrorHandler }
]
})
export class AppModule {}
according to my researches, this error comes from:
Having forgot to decorate the Auth class with #Injectable() or #Inject(Auth)
i have tried doing so by injecting :
#IonicPage()
#Component({
selector: 'page-home',
templateUrl: 'home.html',
})
#Injectable()
export class HomePage {........}
OR
export class HomePage {
constructor(#Inject(Auth) public auth: Auth) {
}
.......
}
But this shows the same error though.
Having a dependency in the Auth constructor that i haven't provided in app.module.ts
as you can see, i've handled this case in my code.
A circular dependency.
which i really think is the issue here, honestly i got a clue how to check this out since i still a beginner.
Hope someone can help