PayPal Rest API, validation_error, Laravel omnipay

Пожалуйста, помогите. я получил

ошибка Неверный запрос - см. подробности

Это из вызова API к PayPal. Что это может быть?

PHP.ini serialize_precision = -1
unit price 25.00 shipping 4.99 = total 29.99

Sandbox и Live дают одну и ту же ошибку:

Сумма товара должна составлять указанную промежуточную сумму (или общую сумму, если сумма не указана) PHP 7.1.15

Это моя песочница вызовов API

запрос:

{
"body": {
    "redirect_urls": {
        "cancel_url": "https://www.**/offer/1/pay/cancel",
        "return_url": "https://www.**/offer/1/pay/success"
    },
    "intent": "sale",
    "payer": {
        "payment_method": "paypal"
    },
    "transactions": [
        {
            "item_list": {
                "items": [
                    {
                        "currency": "EUR",
                        "price": "25.00",
                        "description": "Zustand: Wie neu",
                        "name": "The Crew: Wild Run Edition (PlayStation 4)",
                        "quantity": "1"
                    }
                ]
            },
            "amount": {
                "currency": "EUR",
                "total": "29.99"
            }
        }
    ]
},
"header": {
    "x-pp-ads-performed": "true",
    "content-length": "508",
    "pp_remote_addr": "0.0.0.0.0",
    "x-pp-silover": "name=SANDBOX3.API.1&silo_version=1880&app=apiplatformproxyserv&TIME=2893264986&HTTP_X_PP_AZ_LOCATOR=",
    "accept": "application/json",
    "client-auth": "No cert",
    "host": "api.sandbox.paypal.com",
    "authorization": "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx9NZQ",
    "x-pp-idempotencyid": "b20b59c869af_1522037676",
    "x-slr-orig-script_uri": "https://api.sandbox.paypal.com/v1/payments/payment",
    "x-pp-corrid": "b20b59c869af",
    "user-agent": "Guzzle/3.9.3 curl/7.35.0 PHP/7.1.15",
    "content-type": "application/json",
    "x-pp-slingshot-targetapp": "apiplatformproxyserv"
},
"additional_properties": {},
"method": "POST"}  

отклик:

{
    "status": 400,
    "duration_time": 48,
    "body": {
        "message": "Invalid request - see details",
        "information_link": "https://developer.paypal.com/docs/api/payments/#errors",
        "details": [
            {
                "field": "transactions[0]",
                "issue": "Item amount must add up to specified amount subtotal (or total if amount details not specified)"
            }
        ],
        "name": "VALIDATION_ERROR",
        "debug_id": "b20b59c869af"
    },
    "additional_properties": {},
    "header": {
        "Date": "Mon, 26 Mar 2018 04:14:35 GMT",
        "Paypal-Debug-Id": "b20b59c869af",
        "APPLICATION_ID": "APP-80W284485P519543T",
        "Content-Language": "*",
        "CALLER_ACCT_NUM": "73ES43U4U7R5G"
    }
}