React-router urls don't work when refreshing or writing manually but locally it works ? and webpack is required for routing

Question

I'm using React-router and it works fine while I'm clicking on link buttons, but when I refresh my webpage it does not load what I want.

For instance, I am in localhost/aboutus and everything is fine because I arrived here pressing a link. But If I refresh the webpage i get HTTP Error 404.0 - Not Found The resource you are looking for has been removed, had its name changed, or is temporarily unavailable.

    import React, { Component } from "react";
    import {BrowserRouter, Route, Switch, NavLink} from 'react-router-dom';

   import Home from "./Pages/Home ";
   import AboutUs from "./Pages/AboutUs";
    import ContactUs from "./Pages/ContactUs";
    import Example from "./Pages/Login/Example";
    class App extends Component {
      render() {
        return (

            <Switch>
              <Route exact path="/" exact component={Home} />
              <Route exact path="/Example"  component={Example} />
             <Route exact path="/AboutUs"  component={AboutUs} />
              <Route exact path="/ContactUs"  component={ContactUs} />

              />
            </Switch>
            <Footer />

        );
      }
    }


    export default App;