IBM Security Guardium - RestAPI for Windows GIM clients errors out saying "Function returns a non-json format while setting status to successful"

Problem

I am trying to perform a RestAPI to GET gim_client_params for WINDOWS GIM Clients errors out with following error :

$ curl -k --header "Authorization:bearer cc051d03-8609-4a15-b3cb-84d2d0793a15" -i -H "Content-Type:application/json" -X GET https://xxx-guardium-xx.xxxx.com:8443/restAPI/gim_client_params?clientIP\=xx.xx.x.15
HTTP/1.1 200 OK
X-FRAME-OPTIONS: SAMEORIGIN
X-Permitted-Cross-Domain-Policies: none
X-Content-Type-Options: nosniff
X-XSS-Protection: 1; mode=block
Content-Security-Policy: default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://ibm.biz/GuardiumUpdateCheck https://*.ibm.com; img-src 'self' http
s://*.ibm.com; connect-src 'self'; frame-src 'self' https:; style-src 'self' https: 'unsafe-inline'; font-src 'self' https: 'unsafe-inline'
Set-Cookie: JSESSIONID=583120B413536E3FF9E71698AEB48482; Path=/; Secure; HttpOnly
Cache-Control: max-age=86400
Expires: Wed, 12 Sep 2018 12:46:15 GMT
Access-Control-Allow-Methods: POST, GET, PUT, DELETE
Access-Control-Allow-Headers: authorization, origin, X-Requested-With, Content-Type, Accept
Access-Control-Max-Age: 18000
Content-Type: application/json;charset=UTF-8
Content-Length: 119
Date: Tue, 11 Sep 2018 12:46:14 GMT
Server: SQL Guard

{
"ErrorCode": "2007",
"ErrorMessage": "Function returns a non-json format while setting status to 'successful'"
}