Json Deserialization Error: could not cast or convert from system.string to object

Hi Team,

My Json is looks like below,

{"StatusCode":"0","Message":"Success","Response":"[{\"CatRoot\":{\"CategoryId\":69,\"CategoryName\":\"FOOD\",\"BrandId\":null,\"BrandName\":null},{\"CatRoot\":{\"CategoryId\":69,\"CategoryName\":\"FOOD\",\"BrandId\":null,\"BrandName\":null}}}]}

And I am trying to deserialize, But I am getting an error

"could not cast or convert from system.string to myObject"

    public class CategoryResponse
    {
        public CategoryTree Response { get; set; }
        public string StatusCode { get; set; }
        public string Message { get; set; }
    }

    public class CategoryTree
    {
        public List<CategoryAPI> CatRoot { get; set; }
    }

  public class APISubCategory
    {
        public string CategoryId { get; set; }
        public string CategoryName { get; set; }
        public Brand brand { get; set; }
        public int? ParentAutoID { get; set; }

    }

                    var productResult = JsonConvert.DeserializeObject<CategoryResponse>(response);

So In above line I am getting error, Any help would be appreciated.

Thanks in Advance.