Send C # API file

I have an MVC application in C # which is a WEb system. And I have a C # API that receives calls from the Site. I need to send a file from the Site to the API, I made the code as follows:

Site Code submitting to the API controller

public TRetorno Post<TEnvio, TRetorno>(TEnvio data, Stream arquivo)
    {
        using (var httpClient = this.CriarClient())
        {
            var httpRequest = new HttpRequestMessage
            {
                Method = HttpMethod.Post,
                RequestUri = new Uri(this.endpoint)
            };

            var content = new MultipartFormDataContent();

            content.Add(new StreamContent(arquivo), "file", "filename");                
            content.Add(new ObjectContent<TEnvio>(data, new JsonMediaTypeFormatter()), "model");

            httpRequest.Content = content;

            using (var response = httpClient.SendAsync(httpRequest).Result)
            {
                this.AplicarTratamentoDeRetorno(response);

                return JsonConvert.DeserializeObject<TRetorno>(response.Content.ReadAsStringAsync().Result);
            }
        }
    }

API Driver Code

[AllowAnonymous]
[ActionName("IncluirArquivos")]
public HttpResponseMessage PostArquivos(ImportacaoCredoresModel model)
    {
        var file = HttpContext.Current.Request.Files["file"];

        servicoDeAplicacaoDeImportacao.IncluirArquivoImportacao(model.CodigoCredor, file.InputStream, model.NomeArquivo);
        var arquivos = servicoDeAplicacaoDeRecuperacaoDeImportacoes.ConsultarArquivosImportacao(model.CodigoCredor);

        return Request.CreateResponse(HttpStatusCode.OK, ConversoesImportacao.ConverterEmArquivos(arquivos));
    }

The problem is that when you get the parameter var file = HttpContext.Current.Request.Files["file"]; it is null .

I put the same code on another PC and the parameter does not come null , is it filled with the file? Could it be some IIS configuration? FrameWork version?