Why mozilla changes the characters when i use the .net mvc statement redirect?

Question

I'm trying to redirect to an external website when everything is done, but firefox changes the http word on the url for a weird set of characters. This is my server side code:

    [HttpPost]
    public ActionResult Postular(INFO_BASE_POSTULACION_model pInfoPostulacion) {
        string rutMD5 = Request["rutMD5"];
        int idRegion = Convert.ToInt32(Request["idRegion"]);
        int idInstrumento = Convert.ToInt32(Request["idInstrumento"]);
        string urlDestino = "";

        try
        {
            #region VALIDACION DE DATOS

            if (!ModelState.IsValid) {
                TempData["ModelState"] = ModelState;
                return RedirectToAction("Index", new { data = Utilidades.Base64Encode(rutMD5 + ";" + idRegion + ";" + idInstrumento) });
            }
            #endregion

            INFO_BASE_POSTULACION nuevaInfoBasePostulacion = new INFO_BASE_POSTULACION();
            nuevaInfoBasePostulacion = pInfoPostulacion.modeloToDTO(pInfoPostulacion);
            nuevaInfoBasePostulacion.TOKEN = Utilidades.GenerarStringUnico();
            nuevaInfoBasePostulacion.INFO_REGISTRO_ELIMINADO = false;
            nuevaInfoBasePostulacion.FECHA_CREACION = DateTime.Now;
            Boolean todoOK = new InfoBasePostulacionBO().Agregar(nuevaInfoBasePostulacion);

            if (!todoOK)
            {
                ModelState.AddModelError(String.Empty, "Ocurrió un error al intentar guardar la información.");
                TempData["ModelState"] = ModelState;
                return RedirectToAction("Index", new { data = Utilidades.Base64Encode(rutMD5 + ";" + idRegion + ";" + idInstrumento) });
            }

            string token = nuevaInfoBasePostulacion.TOKEN;
            string idFormulario = Convert.ToString(nuevaInfoBasePostulacion.ID_FORMULARIO_POSTULACION);
            string nombreParamToken = ConfigurationManager.AppSettings["ProActiveOffice-paramNombre-Token"];
            string nombreParamIdFormulario = ConfigurationManager.AppSettings["ProActiveOffice-paramNombre-IdFormulario"];
            urlDestino = ConfigurationManager.AppSettings["ProActiveOffice-URL"] + "?" + nombreParamToken + "=" + token + "&" + nombreParamIdFormulario + "=" + idFormulario;

            //Here i had yo use the uriBuilder because i couldn't make it work on any other way.
            UriBuilder uri = new UriBuilder(urlDestino.Trim());

                //Here i redirect to an external website.
            return Redirect(uri.Uri.ToString());
        }
        catch (Exception ex)
        {
            log.Error("Error al intentar guardar info base de postulación", ex);
            ModelState.AddModelError(String.Empty, "Ocurrió un error al intentar guardar la información.");
            TempData["ModelState"] = ModelState;
            return RedirectToAction("Index", new { data = Utilidades.Base64Encode(rutMD5 + ";" + idRegion + ";" + idInstrumento) });
        }

    }

Here you can see the debug:

1-Here you can see the url string that i have (i had to remove the "http://" because it wasn't working correctly with the uri builder):

2-Here you see the value of the uri builder with the string url in it:

3-Here you see the toString() method apply to the uri (I have already use the absolute uri property):

4-And now finally the error. The http word has been change for a set of characters:

I have had lots of problems with the redirection. These code is currently working on Chrome, but on firefox gives me these error.

What could it be ?

By the way i am using visual studio 2013 + .NET Framerowk 4.5 + MVC4

Answer 1

%E2%80%8B is a URL-encoded, UTF-8 encoded ZERO-WIDTH SPACE character. You likely have one hiding in your application setting file for the ProActiveOffice-URL value. It was maybe pasted in that way, if you copied the URL from somewhere.