CORS issue in file uploading

Hello,

I'm sending file upload request from http://localhost:8080 and getting error

[Error] XMLHttpRequest cannot load https://upload.box.com/api/2.0/files/content. Origin http://localhost:8080 is not allowed by Access-Control-Allow-Origin.

Even I had already added http://localhost:8080 on developer console, below is the screenshot.

Ionic 3 request code is following please have a look:

let headers = new Headers();
        headers.append('Authorization', 'Bearer ' + localStorage.getItem('boxAccessToken'));
        headers.append('Content-Type', 'multipart/form-data');

        let formData = new FormData();

        formData.append('file', 'file://' + path);
        formData.append('attributes',`{"name":"${newName}","parent":{"id":"${folderId}"}}`)

        let headersObject = {
            'headers': headers
        }
        return this._http.post(url, formData, headersObject).map(response => response.json());

Please help me if you have any idea.