"Module" is not part of any NgModule or the module has not been imported into your module

I have an application with some modules.

Here is my root module:

// imports...

@NgModule({
    bootstrap: [ AppModule ],
    declarations: [
        AppComponent,
        ...APP_PIPES // Array with my pipes
    ],
    imports: [ // import Angular's modules
        BrowserModule,
        FormsModule,
        ReactiveFormsModule,
        HttpModule,
        RouterModule.forRoot(ROUTES),
        ...APP_MODULES, // Array with my modules
        ...THIRD_PARTY_MODULES // Array with libs modules
    ],
    providers: [ // expose our Services and Providers into Angular's dependency injection
        ENV_PROVIDERS,
        APP_PROVIDERS
    ]
})
export class AppModule {
 ...
}

And here's ONE of my common modules:

import { CommonModule } from '@angular/common';
import { NgModule } from '@angular/core';

import { MenuComponent } from './menu.component';

@NgModule({
    declarations: [ MenuComponent ],
    exports: [ MenuComponent ],
    imports: [ CommonModule ],
    providers: [ ]
})

export class MenuModule {
  ...
}

I thought it's the correct way to do this, however I'm getting the following error:

AppModule is not part of any NgModule or the module has not been imported into your module

I searched for AppModule in my whole application and I'm using only it in my app.module.ts.

Am I missing to import/export something? Any help would be great. Thanks.

This

bootstrap: [ AppModule ],

should be

bootstrap: [ AppComponent ],

Here you need to pass the AppModule

platformBrowserDynamic().bootstrapModule(AppModule);