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 action:

[HttpPost] [AllowAnonymous] [ValidateAntiForgeryToken] public ActionResult Login(LoginModel model, string returnUrl, string City) { } 

occasionally (once a week), I get the error:

The anti-forgery token could not be decrypted. If this application is hosted by a Web Farm or cluster, ensure that all machines are running the same version of ASP.NET Web Pages and that the configuration specifies explicit encryption and validation keys. AutoGenerate cannot be used in a cluster.

i try add to webconfig:

<machineKey validationKey="AutoGenerate,IsolateApps"       decryptionKey="AutoGenerate,IsolateApps" /> 

but the error still appears occasionally

I noticed this error occurs, for example when a person came from one computer and then trying another computer

Or sometimes an auto value set with incorrect data type like bool to integer to the form field by any jQuery code please also check it.

Answer 1

I just received this error as well and, in my case, it was caused by the anti-forgery token being applied twice in the same form. The second instance was coming from a partial view so wasn't immediately obvious.