Request POST https://apis.nbg.gr/public/sandbox/billpayments/v2/BillPayments/pay content-type: application/json accept: application/json sandbox_id: 5100773314658304 application_id: 3fc6ffe9-5dac-419d-8e6b-5b4012f009bf user_id: e6da8f9c-ee8b-488c-9179-0a566e9d8aed username: User1 provider_id: NBG.gr provider: NBG Response 401 Unauthorized Content-Type: application/json { "httpCode": "401", "httpMessage": "Unauthorized", "moreInformation": "Client id missing." }