Test from application UI is successful but postman says bad request

When i test below URL from applicaton’s API test UI it works


but from postman i get 400 bad request. I have tested GET request for same application and that works so in general there is no issue.

here is my configuration.

Method - POST
Header - “X-App-Request-Key” = “KEY”

Parameters as below:

formatType = json

I also tried to remove opData parameter from parameters tab and put the json data in body tab (raw-data/json)

“param0”: “test_REST_API”,
“param1”: {
“list”: [{
“name”: “sample”,
“value”: “sample”
}, {
“name”: “sample”,
“value”: “sample”
“param2”: -1

then i get 200 OK but then error from application is “Malformed data in the parameter opData”

any suggestion?