The anti-forgery token could not be decrypted

Question

I have a form:

@using (Html.BeginForm(new { ReturnUrl = ViewBag.ReturnUrl })) {
@Html.AntiForgeryToken()
@Html.ValidationSummary()...

and a

Answer 1

I get this error when the page is old ('stale'). A refresh of the token via a page reload resolves my problem. There seems to be some timeout period.