title: Missing token in CORS header ‘Access-Control-Allow-Headers’ from CORS preflight channel
body: <p>Backend returns </p>
  
  <pre><code>Access-Control-Allow-Headers: *
  </code></pre>
  
  <p>I have a request like</p>
  
  <pre><code>fetch('url-here', {
      // ...
      headers: {
          'X-Auth': token,
      }
  })
  </code></pre>
  
  <p>It works in Chrome but for Firefox I'm getting</p>
  
  <blockquote>
    <p>Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at &lt;...cut...>. (Reason: missing token ‘X-Auth’ in CORS header ‘Access-Control-Allow-Headers’ from CORS preflight channel).[Learn More] Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at &lt;...cut...>. (Reason: CORS request did not succeed)</p>
  </blockquote>