title: Axios request blocked regardless of CORS settings - 503 error
body: <p>I've tried just about every suggestion out there to solve a CORS issue (47 different ways to be exact). I'm beginning to think the issue is not on CORS side but in how my axios request is set up. <strong>My question is simple: Is it possible my issue is with my axios setup and not with my server side CORS set up?</strong></p>
  <p><em>Error: Blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.</em></p>
  <p>Frontend React</p>
  <pre><code>  useEffect(async () =&gt; {
        const result = await axios({
          method: &quot;GET&quot;,
          withCredentials: true,
          url: &quot;site-backend.herokuapp.com&quot;,
        }).then((res) =&gt; {
          setMasterUserAccount(res.data.username);
        });
      }, []);
      
  </code></pre>
  <p>Backend Express/Node: CORS</p>
  <pre><code>    const cors = require(&quot;cors&quot;);
      
      var corsOptions = {
        methods: [&quot;GET&quot;, &quot;POST&quot;, &quot;DELETE&quot;, &quot;UPDATE&quot;, &quot;PUT&quot;, &quot;PATCH&quot;],
        origin: &quot;https://site.herokuapp.com&quot;,
        optionSuccessStatus: 200,
        credentials: true,
      };
      
      app.use(cors(corsOptions));
  </code></pre>
  <p>Here's the response from the network tab:</p>
  <pre><code>Request URL: https://site-backend.herokuapp.com/userData
  Request Method: GET
  Status Code: 503 
  Referrer Policy: strict-origin-when-cross-origin
  Cache-Control: no-cache, no-store
  Connection: keep-alive
  Content-Length: 506
  Content-Type: text/html; charset=utf-8
  Date: Wed, 31 Aug 2022 16:54:44 GMT
  Server: Cowboy
  Accept: application/json, text/plain, 
  Accept-Encoding: gzip, deflate, br
  Accept-Language: en-US,en;q=0.9
  Connection: keep-alive
  Host: site-backend.herokuapp.com
  Origin: https://site.herokuapp.com
  Referer: https://site.herokuapp.com/
  Sec-Fetch-Dest: empty
  Sec-Fetch-Mode: cors
  Sec-Fetch-Site: cross-site
  </code></pre>