Ocr space api returns 403 for base64 image data

Hi - Am trying to do OCR with OCR Space API and I get 403 error. I ve given below my sample code. Am trying it in a ionic2 project, feeding the image data from camera option.

let urlSearchParams = new URLSearchParams();
      urlSearchParams.append('base64Image', `data:image/jpeg;base64,${imagedata}`);
      let body = urlSearchParams.toString()
    console.log('jsonbody is::' + JSON.stringify(body));
    let headers = new Headers({
      'Content-Type': 'application/x-www-form-urlencoded' ,
      'apikey': this.apikey  });

    let options = new RequestOptions({ headers: headers });

    return this.http
        .post(this.ocrServiceURL, body, options)
        .map(res => {
            console.log("Response json is:: " + JSON.stringify(res.json()));
            return <string>(res.json().ParsedResults.ParsedText)

If I use something like below, instead of URLSearchParams, I simply get error back that no file or url or base64 data is provided.

var body = {base64Image: `data:image/jpeg;base64,${imagedata}`};

Can someone guide me on what is the right format to provide the data?

Pls let me know if you need more details.