Cannot get property - on Call REST API GET

Oracle Cloud / Cloud Applications / Loyalty / 21c

I had a call works fine when called by POSTMAN

request

https://{{DEV1}}/crmRestApi/resources/11.13.18.05/loyMembers/?q=MemberNumber=19257893065&onlyData=true&limit=1&fields=StixPointsAllowed_c,StatusCode,StixPointBalance_c

response

  "items": [

    {

      "StixPointsAllowed_c": 173914,

      "StatusCode": "ORA_MEM_STATUS_ACTIVE",

      "StixPointBalance_c": 173914

    }

I made a web service REST named: GetMemberRD

with URL=

https://xxx-xxx1.xx.xx1.oraclecloud.com/crmRestApi/resources/111.131.181.105/loyMembers/?q=MemberNumber=##MemNum##&onlyData=true&limit=1&fields=StixPointsAllowed_c,StatusCode,StixPointBalance_c

and select configure Methods: GET and format JSON

I wrote a groovy script to call that web service.

def result = adf.webServices.GetMemberRD.GET("19257893065")

def StixPointBalance_c = result.StixPointBalance_c