title: Calls to local host not working with ReactJS/Axios/Express
body: <p>I am trying to build a full stack app using ReactJS for the frontend and ExpressJS for the backend. I use Axios to make calls from my frontend to my backend. When I make those calls, I get these errors:</p>
  
  <p><img src="https://i.stack.imgur.com/BmHEO.png" alt="Errors in browser console"></p>
  
  <p>My express index file: </p>
  
  <pre class="lang-js prettyprint-override"><code>const express = require('express')
  const path = require('path')
  
  var app = express()
  
  const PORT = process.env.PORT || 5000
  
  app.listen(PORT, () =&gt; {
    console.log(`Server started on port ${PORT}`)
  })
  
  app.use(express.static(path.join(__dirname, "public")))
  </code></pre>
  
  <p>My get call from React frontend: </p>
  
  <pre><code>componentDidMount() {
    axios.get("http://localhost:5000/servers.json").then((res =&gt; {
      this.setState({ servers: res.data })
    }))
  }
  </code></pre>
  
  <p>React server is running on port 3000 and Express server is running port 5000, so there shouldn't be a conflict there...</p>