Getting 400 bad syntax error

I am getting the bad syntax error while using the below syntax in jasper report source parameters section only.

 "source": {
       "reportUnitURI": "/root/report",
       "parameters": {
           "parameterValues" : {
             "REPORT_TIME_ZONE": "America/Los_Angeles"
           }
        }
     },

OUT PUT.

{"message":"There was an error on the server. Try again or contact site administrators. (Error UID: f4f5e092-c24a-44e6-80c6-b24d693c60d3)","errorCode":"serialization.error","errorUid":"f4f5e092-c24a-44e6-80c6-b24d693c60d3"}