 <p>The error is caused by your App timing out. You can either increase the time-out time, but will only reduce the frequency of the issue, or you can:</p> <ol> <li>Rename your index.html to “main.html”</li> <li>Create a new “index.html” and put the following content into it: </li> </ol> <blockquote> <pre><code>&lt;!doctype html&gt; &lt;html&gt; &lt;head&gt; &lt;title&gt;title&lt;/title&gt; &lt;script&gt; window.location='./main.html'; &lt;/script&gt; &lt;body&gt; &lt;/body&gt; &lt;/html&gt; </code></pre> </blockquote> <ol start="3"> <li>Rebuild your app! No more errors!</li> </ol> <p>Another good idea is to give your application a “splash screen”, so that the user gets instant feedback that your app is loading/working, before it is fully ready. </p>