I have a controller with a GetById function

        public Product GetById(int id )
        {

            var query = new Sql().Select("*").From("jf_product").Where<Product>(x => x.Id == id);
            var p = DatabaseContext.Database.Fetch<Product>(query).FirstOrDefault();

            return p;
        }

From the backend I call this and the url is correct http://localhost:56682/umbraco/backoffice/JfpAddon/ProductApi/GetById?id=13

I also can hit a debug marker in GetById and can see that variable p is populated and returned. Yet I get a faulty result in response. The result from the request is just:

)]}',
{}

I found a tip that I could test to use the UmbracoAuthorizedApiController instead, but then the result is just {}

Somewhere the Json serializer don't work as expected. The Product object returned is a poco object.

    [TableName("jf_product")]
    [DataContract(Name = "product")]
    public class Product
    {
        public Product() { }

        [PrimaryKeyColumn(AutoIncrement = true)]
        public int Id { get; set; }

        public string ItemNo { get; set; }
        public string Name { get; set; }
        public string UnitOfMeasure { get; set; }
        public bool IsInStock { get; set; }
        public int SortOrder { get; set; }
        public bool SoldOutWeb { get; set; }
    }