php – Paypal REST API：无法将登录页面设置为开票

我正在使用Paypal REST API和 PHP SDK为慈善机构建立一个捐赠功能.我一直在尝试将着陆页类型设置为“结算”,但似乎没有任何改变.这是我用于定义Web体验配置文件的代码(根据 http://paypal.github.io/PayPal-PHP-SDK/sample/doc/payment-experience/CreateWebProfile.html)：

use PayPalApiFlowConfig;
use PayPalApiPresentation;
use PayPalApiInputFields;
use PayPalApiWebProfile;

$flow = new FlowConfig();
$flow->setLandingPageType('Billing');

$presentation = new Presentation();
$presentation->setLogoImage('xxxxxxxx')
    ->setBrandName('xxxxxxxx')
    ->setLocaleCode('GB');

$inputFields = new InputFields();
$inputFields->setNoShipping(1)
    ->setAddressOverride(0);

$webProfile = new WebProfile();
$webProfile->setName('xxxxxxxx' . uniqid())
    ->setFlowConfig($flow)
    ->setPresentation($presentation)
    ->setInputFields($inputFields);

try {
    $createProfileResponse = $webProfile->create($paypal);
} catch (PayPalExceptionPayPalConnectionException $ex) {
    die($ex);
}

$profileId = $createProfileResponse->getId();

然后是：

$payment = new Payment();
$payment->setIntent('sale')
    ->setPayer($payer)
    ->setRedirectUrls($redirectUrls)
    ->setTransactions([$transaction])
    ->setExperienceProfileId($profileId);

徽标图像在结果页面上显示正常,因此我知道ID有效.我也尝试按照我在网上找到的建议清除cookie,但这没有效果.提前感谢任何建议.