Dynamics CRM Web API POST Products 'Internal Server Error'

Hi,

I've working on a C#.net desktop application to create a products in CRM but when I post my request my response message IsSuccessStatusCode returns false and ReasonPhrase value is "Internal Server Error".

requestUri = https://xxxxxx.xxxxxx.com/api/data/v8.2/products

Content = { "description": "Desc12345", "productnumber": "12345", "name": "Name12345" }

This is for an on-prem. version of CRM and my code to patch/update existing product values all works fine, so I have to assume the Uri isn't the issue.

I've tried including other fields in my content on the assumption that there could be a mandatory value I need to populate but even when I set values to match other products the error still appears.

Can anyone give me suggestions on how I can dig deeper to find details of the error?

Thanks