Postback not working with ASP.NET Routing (Validation of viewstate MAC failed)
I'm using the ASP.NET 3.5 SP1 System.Web.Routing with classic WebForms, as described in http://chriscavanagh.wordpress.com/2008/04/25/systemwebrouting-with-webforms-sample/ All works fine , I have custom SEO urls and even the postback works. But there is a case where the postback always fails and I get a: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster. Here is the scenario to reproduce the error: Create a standard webform