NotFound页面在服务器上不起作用

Question

首先，我的应用程序在localhost上运行良好。除NotFound（404）页面外，每个组件和URL均可在服务器上工作。

<Switch>

        <Route
          exact
          path={'/'}
          render={() => (
          {/*something here*/}
       )} />

       <Route
        exact
        path={'/secondPage'}
        render={() => (
        {/*something here*/}
      )} />

        <Route 
         path={'*'} 
         render={() => (
         <NotFound />
      )} />

 </Switch>

我还尝试了<Route render={() => ( <NotFound /> )} />

Index.js：

ReactDOM.render(
    <BrowserRouter basename={process.env.PUBLIC_URL}><App /></BrowserRouter>, 
    document.getElementById('root')
)

我试图像部署到GitHub页面一样部署React应用。这是我的package.json

{
  "homepage": "https://mywebsite.com/react-app/",

  "dependencies": {
    "escape-string-regexp": "^1.0.5",
    "lodash": "^4.17.10",
    "prop-types": "^15.6.1",
    "react": "^16.3.2",
    "react-dom": "^16.3.2",
    "react-router-dom": "^4.3.1",
    "sort-by": "^1.2.0"
  },
  "devDependencies": {
    "gh-pages": "^1.2.0",
    "react-scripts": "1.1.4"
  },
  "scripts": {
    "predeploy": "npm run build",
    "deploy": "gh-pages -d build",
    "start": "react-scripts start",
    "build": "react-scripts build",
    "test": "react-scripts test --env=jsdom",
    "eject": "react-scripts eject"
  }
}

我想念什么？