please modify your router.module.ts as:
const routes: Routes = [
{
path: '',
redirectTo: 'one',
pathMatch: 'full'
},
{
path: 'two',
component: ClassTwo, children: [
{
path: 'three',
component: ClassThree,
outlet: 'nameThree',
},
{
path: 'four',
component: ClassFour,
outlet: 'nameFour'
},
{
path: '',
redirectTo: 'two',
pathMatch: 'full'
}
]
},];
and in your component1.html
<h3>In One</h3>
<nav>
<a routerLink="/two" class="dash-item">...Go to Two...</a>
<a routerLink="/two/three" class="dash-item">... Go to THREE...</a>
<a routerLink="/two/four" class="dash-item">...Go to FOUR...</a>
</nav>
<router-outlet></router-outlet> // Successfully loaded component2.html
<router-outlet name="nameThree" ></router-outlet> // Error: Cannot match any routes. URL Segment: 'three'
<router-outlet name="nameFour" ></router-outlet> // Error: Cannot match any routes. URL Segment: 'three'