Couldn't send Gatling post request

Hi Team,

I am new for Gatling and for my current project i have stared working on it. I am able to create GET request and get the proper response
But while try to send POST request using Gatling am getting 400 response even provided valid data.

Same POST request with Json file I am able to send by Jmeter and get the response.
So can you please help me to overcode this issue. Below I am sharing post request code and error where i am strucking.

Thanks Advance.

16:44:32.816 [WARN ] i.g.h.a.ResponseProcessor - Request 'Create New Brand: status.find.is(200), but actually found 400
Some Restful Service:
{“timestamp”:“2019-07-19T11:14:32.740Z”,“errorCode”:“BRAND_ALREADY_EXISTS”,“message”:“GS00471392019071940318”,“path”:

http(“Create Quotation”).post(some post path)
.body(RawFileBody("/app/postBrand.json")).asJSON
.headers(headers_1)
.check(status.is(200))
.check(status.is(200), jsonPath("$.validationResult.isValid").is(“true”), jsonPath("$.brandId").exists)
.check(jsonPath("$.brandId").find.saveAs(“brandId”))

Your API is returning a 400 status with a pretty clear error message - that’s where the problem lies