Probleme mit Paypal Plus Plugin 1.4.0

Aus dem Error Log hab ich ständig folgende Fehlermeldung:

Es gibt irgendein Validierungsproblem. Werde aber aus der Fehlermeldung nicht schlau:

[2017-11-09 07:40:39] plugin.ERROR: An error occurred on creating a payment: Client error response [url] https://api.paypal.com/v1/payments/payment [status code] 400 [reason phrase] Bad Request {“exception”:"[object] (GuzzleHttp\Exception\ClientException(code: 400): Client error response [url] https://api.paypal.com/v1/payments/payment [status code] 400 [reason phrase] Bad Request at XYZ/shopware/engine/Shopware/Plugins/Community/Frontend/SwagPaymentPaypalPlus/vendor/guzzlehttp/guzzle/src/Exception/RequestException.php:89)",“response”:"[object] (GuzzleHttp\Message\Response: HTTP/1.1 400 Bad Request\r\nDate: Thu, 09 Nov 2017 06:40:39 GMT\r\nServer: Apache\r\nPaypal-Debug-Id: 46028dcc79588, 46028dcc79588\r\nContent-Language: *\r\nConnection: close\r\nHTTP_X_PP_AZ_LOCATOR: phx02.phx\r\nSet-Cookie: X-PP-SILOVER=name%3DLIVE3.API.1%26silo_version%3D880%26app%3Dapiplatformproxyserv%26TIME%3D1744307034%26HTTP_X_PP_AZ_LOCATOR%3Dphx02.phx; Expires=Thu, 09 Nov 2017 07:10:39 GMT; domain=.paypal.com; path=/; Secure; HttpOnly, X-PP-SILOVER=; Expires=Thu, 01 Jan 1970 00:00:01 GMT\r\nVary: Authorization\r\nContent-Length: 342\r\nContent-Type: application/json\r\n\r\n{“name”:“VALIDATION_ERROR”,“details”:[{“field”:“transactions[0].item_list.items[1].sku”,“issue”:“Must not be blank”},{“field”:“transactions[0].item_list.items[2].sku”,“issue”:“Must not be blank”}],“message”:“Invalid request - see details”,“information_link”:"https://developer.paypal.com/docs/api/payments/#errors",“debug_id”:“46028dcc79588”})"} {“uid”:“cd35aed”}