URL in PWA to second page

Ionic Framework Ionic Angular
1

In my PWA there’s a login page and now I want to navigate by URL to a second page. I’m using the following code in app-routing.module.ts:

const routes: Routes = [
  {
    path: 'login',
    loadChildren: () => import('./pages/login/login.module').then( m => m.LoginPageModule)
  },
  {
    path: '',
    redirectTo: 'login',
    pathMatch: 'full'
  },
  {
    path: 'menu',
    loadChildren: () => import('./pages/menu/menu.module').then( m => m.MenuPageModule),
    canActivate: [AuthService]
  },
  {
    path: 'registration',
    loadChildren: () => import('./pages/registration/registration.module').then( m => m.NeuanmeldungPageModule)
  },
];

The problem is now, that if I call the URL (e.g. https://pwa.myurl.ex) of my PWA first and then the registration URL (e.g. https://pwa.myurl.ex/registration) everything works. But if I clear the cache of my device or browser and call https://pwa.myurl.ex/registration first I get a 404 error.

What’s wrong? Can you help me? Thanks in advance!