Ajax return error when sending Formdata with file to MVC Controller

Question

I have a problem that started to occur for a while. I have a view that sends a FormData with attachment information (input type file) to a MVC controller via an Ajax. The controller returns a Json with some information. It happens that now overnight is being returned to the view where the ajax is and not the controller’s Json.

The strange thing is that running local works. The problem only occurs when the system is hosted.

Follow below the codes:

View

var fileInput = document.getElementById('files');
var formData = new FormData();

for (i = 0; i < fileInput.files.length; i++) {
   formData.append(fileInput.files[i].name, fileInput.files[i]);
}   

$.ajax({
  type: "POST",
  url: "../SistemaRelacionamento/SalvarAnexosRelacionamento",
  data: formData,
  dataType: 'json',                
  contentType: false,
  processData: false,
  success: function (result) {
    alert(result);
},
error: function (jqXHR, textStatus, errorThrown) {
    alert(" Status: " + textStatus + " Http error:" + errorThrown);     
}

}); 

Controller

[HttpPost]
public ActionResult SalvarAnexosRelacionamento()
{   
  try
  {
      List<int> idsAnexos = new List<int>();

      // Grava os anexos do relacionamento
      for (int i = 0; i < Request.Files.Count; i++)
      {
        if (!Directory.Exists(Server.MapPath("~/Uploads/AnexoRelacionamentoFolder/")))
            Directory.CreateDirectory(Server.MapPath("~/Uploads/AnexoRelacionamentoFolder/"));

        var novoNomeArquivo = Guid.NewGuid() + Path.GetExtension(Request.Files[i].FileName);
        var savedFileName = "\\GestorUnimed\\Uploads\\AnexoRelacionamentoFolder\\";
        savedFileName = Path.Combine(savedFileName, Path.GetFileName(novoNomeArquivo));

        var file = Request.Files[i];
        file.SaveAs(Server.MapPath("~/Uploads/AnexoRelacionamentoFolder/") + 
          Path.GetFileName(savedFileName));
        
        var idUltimoAnexo = PegaIdAnexo();

        idsAnexos.Add(idUltimoAnexo);
    }

    return Json(new { success = true, idAnexo = idsAnexos });                            
}
catch (Exception ex)
{
    return Json(new { success = false, idAnexo = 0 });
}
}

Return

return image with error

I’ve searched everywhere and seen no code to send the FormData for controller worked. It seems that the FormData after hosting the system.

Someone can give a light?

Thanks a lot