typescript – 错误：未捕获(承诺)：错误：无法匹配任何路线Angu

我在我的应用程序中实现了嵌套路由。当应用程序加载其显示登录屏幕后登录其重定向到管理页面，其他子路由存在像用户，产品，api等现在当我导航到管理它byddefault加载用户屏幕，但进一步< routeLinks>不工作，它显示这个错误。
错误：未捕获(承诺)：错误：无法匹配任何路线：’product’

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代码主要

import { bootstrap }    from '@angular/platform-browser-dynamic';
import { APP_ROUTER_PROVIDERS } from '../app/app.routes';
import { AppComponent } from '../app/app.component';

bootstrap(AppComponent,[APP_ROUTER_PROVIDERS]);

app.component

import { Component } from '@angular/core';
import { ROUTER_DIRECTIVES } from '@angular/router';

@Component({
  selector: 'demo-app',template: `

    <div class="outer-outlet">
      <router-outlet></router-outlet>
    </div>
  `,directives: [ROUTER_DIRECTIVES]
})
export class AppComponent { }

app.routes

import { provideRouter,RouterConfig } from '@angular/router';

import { AboutComponent,AboutHomeComponent,AboutItemComponent } from '../app/about.component';
import { HomeComponent } from '../app/home.component';

export const routes: RouterConfig = [
  { 
    path: '',component: HomeComponent
   },{
    path: 'admin',component: AboutComponent,children: [
      { 
        path: '',component: AboutHomeComponent
       },{ 
        path: '/product',component: AboutItemComponent 
      }
    ]
  }
];

export const APP_ROUTER_PROVIDERS = [
  provideRouter(routes)
];

home.component

import { Component } from '@angular/core';

@Component({
  selector: 'app-home',templateUrl:'../app/layouts/login.html'
})
export class HomeComponent { }

about.component

import { Component } from '@angular/core';
import { ActivatedRoute,ROUTER_DIRECTIVES } from '@angular/router';

@Component({
  selector: 'about-home',template: `<h3>user</h3>`
})
export class AboutHomeComponent { }

@Component({
  selector: 'about-item',template: `<h3>product</h3>`
})
export class AboutItemComponent { }

@Component({
    selector: 'app-about',templateUrl: '../app/layouts/admin.html',directives: [ROUTER_DIRECTIVES]
})
export class AboutComponent { }