title: `expo start` in development stuck at "Tunnel Connected", QR code is unusable
body: <p>I'm currently running a detached expo project in development mode. Whenever I run <code>expo start</code> or <code>npm start</code> in the terminal I get the following logs:</p>
  
  <pre><code>$ expo start                                                                                                                                                                      
  Starting project at /Users/johncd/workspace
  Expo DevTools is running at http://localhost:19002
  Starting Metro Bundler on port 19001.
  Tunnel ready.
  Your native app is running at expb675c828acbb437095bc6218883f56bb://192.168.1.12:19000
  Logs for your project will appear below. Press Ctrl+C to exit.
  </code></pre>
  
  <p><strong><em>The expected results</em></strong> would include a QR code after these logs, but there is none.</p>
  
  <p>When I visit the DevTools at localhost:90002 I see the metro bundler is running on LAN and a QR code is available. However, when I scan this QR code, it results in an error reading <strong><em>"No usable data found".</em></strong></p>
  
  <p><a href="https://i.stack.imgur.com/6stcd.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/6stcd.jpg" alt="No usable data found when scanning QR code"></a></p>
  
  <ul>
  <li><p><strong><em>I've tried</em></strong> checking for a Firewall (System preferences > Privacy > Firewall) but it appears to be turned off.</p></li>
  <li><p>I have also tried uninstalling and re-installing <code>expo-cli</code> as well as the project and running <code>expo start</code> again but to no avail.</p></li>
  <li><p>I've tried using <code>npm start</code> and <code>yarn start</code>. I have also tried running the project on a tunnel.</p></li>
  <li><p>I created a test project using <code>expo init test-project</code> and successfully ran it using <code>expo start</code>, so it seems this issue is only occurring on this project.</p></li>
  <li><p>I also tried running <code>expo start --clear</code> to clear the cache.</p></li>
  </ul>
  
  <p>None of these have worked.</p>
  
  <p>Any help is appreciated!</p>
  
  <p>Versions:</p>
  
  <pre><code>    "expo": "^33.0.0",
      "expo-constants": "^5.0.1",
      "expokit": "^33.0.4",
      "react": "16.8.3",
      "react-native": "https://github.com/expo/react-native/archive/sdk-33.0.0.tar.gz",
      "react-native-unimodules": "^0.4.2",]
  </code></pre>
  
  <p>Running on OSX</p>