Error on API Call

I am getting the following error when using the api connector to call an api. Works just fine in POSTMAN sending a blank {} object in the body. But no matter what i put in the body here, i get the following error.

There was an issue setting up your call.

Raw response for the API
Status code 400
“error”: {
“code”: null,
“message”: “You submitted a length-0 POST body, but must submit a JSON object. (HINT: Try submitting an empty object instead, i.e. {}. If you’re using curl, you can pass -d ‘{}’ -H ‘Content-Type: application/json’)”,
“param”: null,
“type”: “invalid_request_error”

Add the content type in the header
Content-Type: application/json’
And why do you have both parameters AND json body?
Can you provide url to API Doc?