Web api post request from postman is Not working

Hi

  Created one web api where we are starting a process  with one CDT as an input . When sending data like {["employeeName":"test",}]in the appian body and test request its working fine.

But triggering the same from post man we are getting a 500 error. Web api authentication is happened properly .

a!startProcess(
processModel: cons!employee_processweb,
processParameters: {employeedetails:a!fromJson(
http!request.body
)},
onSuccess: a!httpResponse(
statusCode: 200,
headers: {
a!httpHeader(name: "Content-Type", value: "application/json")
},
body: a!toJson(
fv!processInfo
)
),
onError: a!httpResponse(
statusCode: 500,
headers: {
a!httpHeader(name: "Content-Type", value: "application/json")
},
body: a!toJson(
{
error: "There was an error starting the process"
}
)
)
)

Postman:

Configured header with Content-Type:application/json

sending API Key bearer token.

Body format as JSON.