title: Access to fetch at has been blocked by CORS policy while accessing from another subdomain
body: <p>I have been getting below errors while trying to access graphql url from <a href="https://subdomain-b.abc.com/" rel="nofollow noreferrer">https://subdomain-b.abc.com/</a> service. </p>
  
  <pre><code>POST https://subdomain-a.abc.com/graphql 504
  
  Access to fetch at 'https://subdomain-a.abc.com/graphql' from origin 'https://subdomain-b.abc.com/' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.
  </code></pre>
  
  <p>Both services are running on same aws account on Fargate with ELB sitting in front of them. Route 53 is redirecting requests to ELB.</p>
  
  <p>Most of the answers I googled are related to S3 bucket which is not the case with my setup. Let me know if I can provide some more details.</p>