Problem with Passing data to the service using dependnancy injection

[hokrc01]

First, great tutorial. I am having the same problem, Ross Rowlins reported. Specifically, unless I explicitly put a provide in the app.component.ts providers: [DialogService, DialogConfig]

I get the following error :
ERROR NullInjectorError: R3InjectorError(AppModule)[DialogService -> DialogService -> DialogService]:
NullInjectorError: No provider for DialogService!

Thanks for the additional insight.