returning blank autocomplete

I do a search in my database to search for product names without exceptions (I do not know if it's relevant, but this return is a string list)

var listaDosProdutos = _servico.ObterNomeDosProdutos();

Then I take this list and do a search of which product starts with the typed name and repost in json format

var listaFiltroProdutos = listaDosProdutos.Where(str => str.ToLower().StartsWith(Prefix.ToLower())).ToList();

Controller code:

[HttpPost]
public JsonResult ConsultaProduct(string Prefix)
{
    //Searching records from list using LINQ query
    var listaDosProdutos = _servico.ObterNomeDosProdutos();
    var listaFiltroProdutos = listaDosProdutos.Where(str => str.ToLower().StartsWith(Prefix.ToLower())).ToList();

    return Json(listaFiltroProdutos);
}

Inside my _Layout layer I'm loading two Jquery cdn

<script src="https://ajax.aspnetcdn.com/ajax/jquery/jquery-3.3.1.min.js"asp-fallback-src="~/lib/jquery/dist/jquery.min.js"
        asp-fallback-test="window.jQuery"
        crossorigin="anonymous"
        integrity="sha384-tsQFqpEReu7ZLhBV2VZlAu7zcOV+rXbYlF2cqB8txI/8aZajjp4Bqd+V6D5IgvKT">
</script>

and

 <script src="https://code.jquery.com/ui/1.12.1/jquery-ui.min.js"integrity="sha256-VazP97ZCwtekAsvgPBSUwPFKdrwD3unUfSGVYrahUqU="
            crossorigin="anonymous"></script>

In my cshtml page I have. My input field text

@using (Html.BeginForm("Index", "Product", FormMethod.Get, new { @class = "navbar-form navbar-left" }))
{
          <input type="text" class="form-control focus" id="consultarProduto" name="consultarProduto" placeholder="Search by Name, CasNo, Class, Group Name ...">
          <button type="submit" class="btn btn-default">Submit</button>
}

And my js

$("#consultarProduto").autocomplete({
            source: function (request, response) {
                $.ajax({
                    url: "/Product/ConsultaProduct",
                    type: "POST",
                    dataType: "json",
                    data: { Prefix: request.term },
                    success: function (data) {
                        response($.map(data, function (item) {
                            return { label: item.CommercialName, value: item.CommercialName };
                        }))
                    }
                })
            }
        });

I did some tests with other codes: link

But I did not succeed.