Access to XMLHttpRequest at 'http://localhost:8000/oauth/token' from origin react app has been blocked by CORS

Question

I am using oauth2 in springboot for the server side and React application on the Client. I am sending the token request for the grant_type client_credentials to /oauth/token from react application and get the Above error.

I have used @CrossOrigin and also used http.cors() for the global security config but still keep seeing the Preflight cors block error in browser console.

Error:

Access to XMLHttpRequest at 'http://localhost:8000/oauth/token' from origin 'http://localhost:3000' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: It does not have HTTP ok status. xhr.js:177 POST http://localhost:8000/oauth/token net::ERR_FAILED

Answer 1

https://www.youtube.com/watch?v=7Yqb275FKmY helped me up. The issue was the @Order(Ordered.HIGHEST_PRECEDENCE) on my SimpleCORSFilter class that implements filter class.