We have deployed our API's on amazon ec2 and we are using these API's on our frontend react.js. We already have set the headers 'Access-Control-Allow-Origin' to '*' in backend

// Preflight API
static setPreflight = async () => {

    const config = {
        headers: {
            'Authorization': `Bearer ${sessionStorage.getItem('authData')}`
        }
    }
    await axios.options(`http://-------/preflight`, config)
}

when we call this function only once to set headers for preflight but we got this error

Access to XMLHttpRequest at 'http://ec2-13-125-149-247--------/preflight' from origin 'http://localhost:3000' has been blocked by CORS policy: The 'Access-Control-Allow-Origin' header contains multiple values '*, *', but only one is allowed.

How to resolve this type of error on react.js?