Can't bind to 'ngForTrackby' since it isn't a known property of 'app-card'. code example
Example: Can't bind to 'ngForOf' since it isn't a known property of 'div'.
// older Angular versions
// import {BrowserModule, CommonModule} from '@angular/common';
import { BrowserModule } from '@angular/platform-browser'
..
..
@NgModule({
imports: [BrowserModule, /* or CommonModule */],
..
})