title: create react app - access "On your network" doesn't work
body: <p>I'm using create-react-app project. I try to test my localhost:3000 app on my iphone. </p>
  
  <p>When I start an app <code>yarn start</code> I get this message:</p>
  
  <blockquote>
    <p>Compiled successfully!</p>
    
    <p>You can now view front-client in the browser.</p>
    
    <p>Local:            <a href="http://localhost:3000/" rel="nofollow noreferrer">http://localhost:3000/</a>   On Your Network: 
    <a href="http://172.20.10.5:3000/" rel="nofollow noreferrer">http://172.20.10.5:3000/</a></p>
  </blockquote>
  
  <p>But when I go to <a href="http://172.20.10.5:3000/" rel="nofollow noreferrer">http://172.20.10.5:3000/</a> the browser window just spins and nothing happens. </p>
  
  <p>I have the firewall on my mac set off.</p>
  
  <p>I also tried setting host to 0.0.0.0 like they suggest <a href="https://stackoverflow.com/questions/47412363/how-to-open-a-create-react-app-from-another-computer-connected-to-the-same-netwo">here</a> but it didn't work:</p>
  
  <blockquote>
    <p>$ HOST=0.0.0.0 NODE_PATH=src react-scripts start Attempting to bind to
    HOST environment variable: 0.0.0.0 If this was unintentional, check
    that you haven't mistakenly set it in your shell. Learn more here:
    <a href="https://facebook.github.io/create-react-app/docs/advanced-configuration" rel="nofollow noreferrer">https://facebook.github.io/create-react-app/docs/advanced-configuration</a></p>
  </blockquote>
  
  <p>What might be the reason that I cannot access this app on my network?
  Is there any other way to test it?</p>