yel-dspace-angular/src/app/app-routing.module.ts

import { NgModule } from '@angular/core';
import { RouterModule } from '@angular/router';

import { PageNotFoundComponent } from './pagenotfound/pagenotfound.component';
@NgModule({
  imports: [
    RouterModule.forChild([
      { path: '', redirectTo: '/home', pathMatch: 'full' },
      { path: '**', pathMatch: 'full', component: PageNotFoundComponent},
    ])
  ],
})
export class AppRoutingModule { }