How to display the error No permissions?

Question

Angular

i have this router

{
        path: 'login',
        component: LoginLayoutComponent,
     
    },
  {
        path: 'dashboard',
        component: MainLayoutComponent,
        canActivate: [AuthGuard],
        data: { role: 'admin' },
    },

And AuthGuard with the canActivate method.

canActivate(route: ActivatedRouteSnapshot) {
        let user : User = this.userService.getCurrentUser();
        let role = route.data['role'];

        //console.log(route.url[0].path);

        if(user.role == role) {
            return true;
        } else {
            if(permissionDependence[user.role][role]) {
                return true;
            } else {
                //this.router.navigate(['/permission/'])
            }
        }

        // not logged in so redirect to login page
        this.router.navigate(['/login']);
        return false;
    }

How can I make it throw an error if there are no rights? And then nothing happens to me.