Again, we have to register the new component within the app.module.shared.ts file:
[...]
import { LoginFacebookComponent } from './components/login/login.facebook.component';
import { LoginExternalProvidersComponent } from './components/login/login.externalproviders.component';
@NgModule({
declarations: [
[...]
LoginFacebookComponent,
LoginExternalProvidersComponent,
[...]