[React] Access to XMLHttpRequest at '주소A' from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resou..

Access to XMLHttpRequest at '주소A' from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource.

https://snowdeer.github.io/openshift/2020/06/13/react-for-cors-using-proxy/

React CORS 문제 해결하기(Proxy 이용) · snowdeer's Code Holic