我正试图将PayPal付款集成到我的应用程序中，因为我希望用户能够向另一个用户汇款，但它给了我错误400。我试着把我朋友的PayPal电子邮件只是为了测试它，我知道它不会汇款，因为它是在沙箱。

const makePayout = async () => { 

    try {
      const response = await fetch('https://api-m.sandbox.paypal.com/v1/payments/payouts', {
        method: 'POST',
        headers: {
          'Content-Type': 'application/json',
          'Authorization': 'Bearer <my access token>'
        },
        body: JSON.stringify({
          "sender_batch_header": {
            "sender_batch_id": "Payouts_2020_100007",
            "email_subject": "You have a payout!",
            "email_message": "You have received a payout! Thanks for using our service!"
          },
          "items": [
            {
              "recipient_type": "EMAIL",
              "amount": {
                "value": "10.00",
                "currency": "PHP"
              },
              "note": "Thanks for your patronage!",
              "sender_item_id": "201403140001",
              "receiver": "<friend's email>@gmail.com",
              "recipient_wallet": "RECIPIENT_SELECTED"
            }
          ]
        })
      });

      if (response.ok) {
        const data = await response.json();
        console.log('Payout success:', data);
      } else {
        console.log('Payout failed. Status:', response.status);
      }
    } catch (error) {
      console.error('Payout error:', error.message);
    }
  };

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