Angular Second Layer Navigation dispear after click on link - lazy-loading

Question

I have two layer navbar and the app is using Lazy loading, but every time I clcik on Team Management button the component is working but the Admin Panel navbar is dispear:
Here is my admin-routing.module.ts:
const routes: Routes = [
{ path: '', component: AdminComponent },
{
path: 'team',
loadChildren: () => import('./team/team.module').then((m) => m.TeamModule),
},
];
#NgModule({
imports: [RouterModule.forChild(routes)],
exports: [RouterModule],
})
export class AdminRoutingModule {}
Here is HTML for the admin.component.html:
<div>
<nav class="navbar navbar-expand-sm navbar-light bg-light mb-3">
<div class="container">
<a class="navbar-brand" href="#">Admin Panel</a>
<button
class="navbar-toggler"
data-toggle="collapse"
data-target="#team-navbarNav"
>
<span class="navbar-toggler-icon"></span>
</button>
<div class="collapse navbar-collapse" id="team-navbarNav">
<ul class="navbar-nav">
<li class="nav-item">
<a class="nav-link" href="/team" routerLink="team"
>Team Management</a
>
</li>
<li class="nav-item">
<a class="nav-link" href="">Others</a>
</li>
</ul>
</div>
</div>
</nav>
</div>
<router-outlet></router-outlet>
Here is the result of after click on Team Management button:
As you can see the second navbar is gone, I do set up
<router-outlet></router-outlet>
in admin.component.html, but it feels like never works..
team is the sub component of admin.
admin-routing. module.ts:
Here is my Github repo:
https://github.com/qwe3804132/BusyQA-CRM/tree/main/CRMFrontEnd
any suggestions?