Error in Groovy Script while calling Change Status for Approval

Summary:

Hello Experts,

I am trying to call change status via groovy script by building the connection through other web services functionality in PBCS. Below is the error response from JASON,

Log messages : 

jsonResponse Status:500

jsonResponse Status_txt:

Kindly go through the below groovy script and let me know if there is any issue with the code.

Content (please ensure you mask any confidential information):

def Payload="""{

actionId=6&pmMembers=BU_5120&comments=promoted}"""

HttpResponse<String> jsonResponse = operation.application.getConnection("PUH")

.post("/planningunits/Budget::Manpower Working/actions/")

.header("Content-type","application/x-www-form-urlencoded")

.body(Payload).asString();

println "jsonResponse Status:"

println jsonResponse.status

println "jsonResponse Status_txt:"