PayPal iOS SDK不适用于实时凭据

Question

PayPal SDK：请求失败，错误：UNKNOWN_ERROR - 系统错误（UNKNOWN_ERROR）。请稍后再试。 （400）| PayPal Debug-ID：3e8087cbf6bd1 [live，PayPal iOS SDK 2.1.2]

配置：

// Set up payPalConfig
    _payPalConfig = [[PayPalConfiguration alloc] init];
    _payPalConfig.acceptCreditCards = YES;
    _payPalConfig.languageOrLocale = @"en";
    _payPalConfig.merchantName = @"MERCHANT NAME.";
    _payPalConfig.merchantPrivacyPolicyURL = [NSURL URLWithString:@"https://www.paypal.com/webapps/mpp/ua/privacy-full"];
    _payPalConfig.merchantUserAgreementURL = [NSURL URLWithString:@"https://www.paypal.com/webapps/mpp/ua/useragreement-full"];

PayPalItem *selectedtemInfo = [PayPalItem itemWithName:productDetails
                                              withQuantity:1
                                                 withPrice:[[NSDecimalNumber alloc] initWithString:totalCostofProducts]
                                              withCurrency:@"USD"
                                                   withSku:nil];

PayPalPayment *payment = [[PayPalPayment alloc] init];
    payment.amount = total;
    payment.currencyCode = @"USD";
    payment.shortDescription = @Description";
    payment.items = selectedProductsItems;
    payment.paymentDetails = paymentDetails; 

PayPalPaymentViewController *paymentViewController = [[PayPalPaymentViewController alloc] initWithPayment:payment
                                                                                                    configuration:self.payPalConfig
                                                                                                         delegate:self];