title: Azure Applications Insights node js module not working - Fetch API cannot load error
body: <p>I am trying to integrate npm's application insights module (<a href="https://www.npmjs.com/package/applicationinsights" rel="nofollow noreferrer">https://www.npmjs.com/package/applicationinsights</a>) into my React js application.</p>
  
  <p>My source for doing this is:</p>
  
  <pre><code>import appInsights from 'applicationinsights';
  appInsights.setup(applicationInsightsKey).start();
  </code></pre>
  
  <p>The problem I got is that in my Chrome Developer tools I can see a preflight request made to <a href="https://dc.services.visualstudio.com/v2/track" rel="nofollow noreferrer">https://dc.services.visualstudio.com/v2/track</a>. 
  But in the console I can see the following error:</p>
  
  <blockquote>
    <p>"Fetch API cannot load <a href="https://dc.services.visualstudio.com/v2/track" rel="nofollow noreferrer">https://dc.services.visualstudio.com/v2/track</a>.
    Request header field content-encoding is not allowed by
    Access-Control-Allow-Headers in preflight response."</p>
  </blockquote>
  
  <p>Do you have an idea how can I fix this issue?</p>