title: Problem with vue router, history mode not working on second layer
body: <p>I have a vuejs project that uses vue router
  i made a dashboard for my website and i wanted to add a second router to project for it</p>
  
  <pre><code>import Vue from 'vue'
  import Router from 'vue-router'
  import Index from "@/views/Admin/Index.vue";
  import ContactIndex from "@/views/Admin/Contact/Index.vue";
  
  Vue.use(Router)
  
  const router = new Router({
      mode: "history",
      routes: [{
              path: '/admin',
              name: 'admin',
              component: Index,
              meta: {
                  requireAuth: true
              }
          },
          {
              path: '/admin/contact',
              name: 'contact',
              component: ContactIndex,
              meta: {
                  requireAuth: true
              }
          }
      ]
  })
  export default router;
  </code></pre>
  
  <p>the issue is when i tried to open let's say "/admin/contacts" in my browser manually or refreshed the page, contact didn't load up and i got 404 error</p>
  
  <p>BUT, when i click on the router-link tag that is linked to that address it works as intended</p>
  
  <p>How can i fix it?</p>