Problem with CORS in Reactjs application

Question

I checked on other questions but found no answer that fits my problem.

I have a Reactjs application that is on my localhost:3000 and I need to post for my API that is on my localhost:4000.

The sending of the data is blocked by CORS, but so far, I have done other tests in my API and everything is working correctly. I can even make the same request through India.

CORS API:

module.exports = (req, res, next) => {
    res.header('Access-Control-Allow-Origin', '*')
    res.header('Access-Control-Allow-Methods', 'GET,POST,PATCH,DELETE')
    res.header('Access-Control-Allow-Headers', 'Origin, X-Requested-with, Cotent-type, Accept, privatekey')
    next()
}

Requests in the React app are via Axios. Error: