Posted model's properties always null

Just saying I'd rather not make changes to my client app since it still need to use my old api, written in asp.net web api.

I believe I'm doing exactly the same thing in both my old api and the .core api, but with the latter, the model's properties posted are all null/empty/0

I did add json formatters to the .core api's mvc.start()

"Old Api"

        [HttpPost, Route("products/search")]
        public IHttpActionResult Search(ProductSearchViewModel search)
        {
            var result = new ProductSearchResult();
// get the data
            return Ok(result);

        }

New Api

        [HttpPost, Route("search")]
        public ProductSearchResultsViewModel Search( Product SearchViewModel search)
        {
            var data = _repository.Search(search.Search);
            var result = new ProductSearchResultsViewModel
            {
                Deals = data.Select(item => new ProductSearchResultViewModel
                {
                    Id = item.Id,
                    // etc
                }).ToList()
            };
            return result;
        }

I experimented with [FromBody] but then the api return a media type not supported error