Cross-Origin Request Blocked with React and Express

Question

So I hit this error, when I was trying to send data to the back end using React. From what I learnt I need to allow the communication on the back-end and in the .htacc

Answer 1

you have to allow OPTIONS method as well

res.setHeader('Access-Control-Allow-Methods', 'POST, OPTIONS');

the browser send it with any post request to other domain to check how it will communicate with this remote server.