title: No 'Access-Control-Allow-Origin' header is present on the requested resource even though there is?
body: <p>I'm trying to make a POST request from <a href="https://www.example.io" rel="nofollow noreferrer">https://www.example.io</a> (client) to <a href="https://api.example.io" rel="nofollow noreferrer">https://api.example.io</a> (server) which has this CORS configuration:</p>
  <pre><code>app.use(
    cors({
      origin: https://www.example.io
      credentials: true,
      maxAge: 86400,
      allowedHeaders:
        &quot;Access-Control-Allow-Headers, Origin, Accept, X-Requested-With, Content-Type, Cookie, Host, Access-Control-Request-Method, Access-Control-Request-Headers&quot;,
      methods: [&quot;GET&quot;, &quot;POST&quot;, &quot;PUT&quot;, &quot;DELETE&quot;, &quot;OPTIONS&quot;, &quot;HEAD&quot;],
    })
  );
  </code></pre>
  <p>The origin header is not only present but matches the origin domain.</p>
  <p>Exact error message:</p>
  <pre><code>Access to XMLHttpRequest at 'https://api.example.io/application/create' from origin 'https://www.example.io' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.
  </code></pre>
  <p>Any help would be greatly appreciated.</p>