The required anti-forgery cookie "__Requestverificationtoken" is not present

Question

I have a project that is on my server iis and is working on most machines, but in some of them the message is received:

The required anti-forgery cookie "__RequestVerificationToken" is not present. 

I have in my controller:

 [HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Salvar(Ramal ramal, HttpPostedFileBase upload, int CallSource)
        {

            ViewBag.CallSource = CallSource;

            if (ModelState.IsValid)
            {
                string AuxExtensao;
                byte[] auxFoto;

and in my view:

@model Ramais.Models.Ramal

@using (Html.BeginForm("Salvar", "Ramais", new { CallSource = (int)ViewBag.CallSource }, FormMethod.Post,
    new { enctype = "multipart/form-data" }))
{

    @Html.AntiForgeryToken()

I have 50 machines ok and two displaying this message when the user saves the information. If the same goes on another machine works...

Someone’s been through this?