重定向后PayPal Sandbox 400错误

我使用laravel V6

$apiContext = new \PayPal\Rest\ApiContext(
        new \PayPal\Auth\OAuthTokenCredential(
            'token..',
            'token..'
        )
    );

   //dd($transaction);
    $callbackUrl = url('/paypal/status');

    $payer = new \PayPal\Api\Payer();
    $payer->setPaymentMethod('paypal');

    $amount = new \PayPal\Api\Amount();
    $amount->setTotal('1.00');
    $amount->setCurrency('USD');

    $transaction = new \PayPal\Api\Transaction();
    $transaction->setAmount($amount);

    $redirectUrls = new \PayPal\Api\RedirectUrls();
    $redirectUrls->setReturnUrl($callbackUrl)
        ->setCancelUrl($callbackUrl);

    $payment = new \PayPal\Api\Payment();
    $payment->setIntent('sale')
        ->setPayer($payer)
        ->setTransactions(array($transaction))
        ->setRedirectUrls($redirectUrls);

    try {
        $payment->create($apiContext);
        //dd($payment);
        //dd($payment->getApprovalLink());
        return redirect()->away($payment->getApprovalLink());
    } catch (\PayPal\Exception\PayPalConnectionException $ex) {
        var_dump(json_decode($ex->getData()));
        exit(1);
    }

那是控制器，我按照说明文件在此处输入链接描述，但出现400错误，在此处输入链接描述。它生成的链接如下所示：https://www.sandbox.paypal.com/webapps/hermes?flow=1-P&ulReturn = true＆token = EC-88M93704JL735000S＆country.x = US＆locale.x = es_XC＃/ checkout / genericError？code = UEFZTUVOVF9ERU5JRUQ％3D

我不明白为什么错误.. client_id机密是可以的..无论如何，它直接在控制器中，并检查沙盒帐户是否有余额