I am using Angular 4 project and I have used ngSwitch to switch multiple layouts based on condition. So, at this time, I am getting error cannot find primary outlet to load Component. It is because of router-outlet but what is the best way to solve this ?

Code :

<div [ngSwitch]="isAuthenticated()">
  <div *ngSwitchCase="true">
    <div id="wrapper">
      <navbar></navbar>
      <div class="gray-bg">
        <router-outlet></router-outlet>
        <footer></footer>
      </div>
    </div>
  </div>
  <div *ngSwitchCase="false">
    <div class="blue">
      <router-outlet></router-outlet>
      <footer></footer>
    </div>
  </div>
</div>