JS PayPal REST错误：MALFORMED_REQUEST

Question

我尝试将PayPal API集成到我的应用中。当我尝试在脚本中调用API时，出现错误：
传入的JSON请求未映射到API请求。这是错误的全部对象：

  

debug_id：“ 8280412cbada”   information_link：“ https://developer.paypal.com/webapps/developer/docs/api/#MALFORMED_REQUEST”

     

消息：“传入的JSON请求未映射到API请求”      名称：“ MALFORMED_REQUEST”

但是当我尝试通过EasyRest使用相同的参数进行呼叫时，一切正常。

这是我用来打电话的代码：

function payPalStep3(gAccessToken, gPrice, gCurrency, gOrderNumber){ return new Promise((resolve, reject) => {

let newPayment = {
  intent: 'sale',
  redirect_urls: {
    return_url: 'http://localhost:3000/success.html', 
    cancel_url: 'http://localhost:3000/reject.html'
  },
  payer: {
    payment_method: 'paypal'
  },
  transactions: [{
    amount: {
      total: parseFloat(gPrice),
      currency: gCurrency
    }
  }]
}

let req = new XMLHttpRequest(); 
  let UrlReq = 'https://api.sandbox.paypal.com/v1/payments/payment'; 
  req.open('POST', UrlReq, true); 
  req.setRequestHeader('Content-Type', 'application/json'); 
  req.setRequestHeader('Authorization', 'Bearer '+gAccessToken);
  req.onreadystatechange = function(){
    if(req.readyState == 4){
    let shopUserResponse = req.response;
    shopUserResponse = JSON.parse(shopUserResponse);

      resolve(shopUserResponse); 
    }
    req.onerror = () => err(false);
  }
  req.send(newPayment) })}

也许有人可以帮助我。