Getting 500 error while sending the request through rest assured automation

Question

I'm getting 200 code when passing all required headers into postman, but when i try running through automation, i get an error 500

Below is the mentioned error message:

{"error":{"code":"500","message":"Internal Server Error","errors":[{"message":"[ISS.0086.9249] Missing Parameter: jsonString"}]},"request_tracking_id":"765666"}

I am expecting a solution. What do i need to change? Is it a server proablem? Is the request body the problem?