Unable to authorize while making api call using fetch

Question

react code to fetch api data

    getData = () => {
        const url = FormatUrl(`/cluster`)
        fetch(url,  { 
        method: 'GET', 
        headers: new Headers({
            'Authorization': 'Basic my_token', 
            'Content-Type': 'application/x-www-form-urlencoded'
    })})
        .then(res => res.json())
        .then(res => {
            console.log(res, "=")
        })
    }

error:

    Access to fetch at 'https://beta.cnox.io:3001/cluster' from origin 'http://localhost:3000' has been blocked by CORS policy: Request header field authorization is not allowed by Access-Control-Allow-Headers in preflight response.
    beta.cnox.io:3001/cluster:1 Failed to load resource: net::ERR_FAILED

Here i am trying to fetch data from above api and sending token also but getting below error. Same api is working from angular. please take a look