I also faced the same problem, and I searched the Internet so much, but I didn’t get any answer according to my question.

So I uninstalled version 6 of react-router-dom:

npm uninstall react-router-dom

And installed version 5.2.0 of react-router-dom:

npm install [email protected]

use below 

import {
  BrowserRouter as Router,
  Switch,
  Route,
  Link
} from "react-router-dom";



export default class App extends Component {

  render() {
    return <div>
      <Router>
      < Navbar />
     
    
     <Switch>
          <Route path="/business">
              <News pageSize={4} category="business"/>
          </Route>

          <Route path="/entertainment">
              <News pageSize={4} category="entertainment"/>
          </Route>

          <Route path="/general">
            <News pageSize={4} category="general"/>
          </Route>
        </Switch>


      </Router>
      
    
    </div>;
  }
}

reference - Link Here


    

For v6 use below

 
import React, { Component } from 'react';
import Navbar from './Components/Navbar';
import News from './Components/News';

import { BrowserRouter as Router, Route, Routes } from 'react-router-dom'
export default class App extends Component {

  render() {
    return <div>
      <Router>
        < Navbar />
        <Routes>
            <Route exact path="/" element={<News pageSize={8} category="general"/>}/>
            <Route exact path="/business" element={<News pageSize={4} category="business"/>}/>
            <Route exact path="/entertainment" element={<News pageSize={4} category="entertainment"/>}/>
            <Route exact path="/general" element={<News pageSize={4} category="general"/>}/>
        </Routes>
      </Router>
    </div>;
  }
}