>The server refused this request because the request entity is in a format not supported by the requested resource for the requested method. RAW

accepted

I bet that call from Postman does not include Content-Type: application/json.

HTTP 415 means that the server does not understand the media format of the request. In your controller you are specifying it accepts JSON, but you have not said if the request indicated that the body is in that format. Just because you put the data in JSON format, does not mean that the server is going to recognize it, you have to indicate it iContent-Type header.