贝宝退款API出现未经授权的错误

Question

 const { paymentId } = req.body;

const refundURI = `https://api.sandbox.paypal.com/v2/payments/captures/${paymentId}/refund`;
// get access token
const { access_token } = await generateToken();
// console.log(JSON.stringify(access_token));

const refundObj = await Axios.post(refundURI, {
  headers: {
    Accept: `application/json`,
    Authorization: `Bearer ${access_token}`,
  },
  body: JSON.stringify({
    amount: {
      currency_code: "USD",
      value: "10.00",
    },
  }),
});

我正在尝试退还Paypal付款。我正在生成访问令牌，但仍未提供401状态码的授权。