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 ran into this issue in an area of code where I had a view calling a partial view, however, instead of returning a partial view, I was returning a view.

I changed:

return View(index);

to

return PartialView(index);

in my control and that fixed my problem.