Validation of viewstate MAC failed -View State Error
<p>In my website, when a web page is idle for more than 5 minutes, then that page is not working until I refresh. The following error occurs:</p>

<blockquote>
  <p>Error:
  Sys.WebForms.PageRequestManagerServerErrorException:
  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.</p>
</blockquote>

<p>I'm already using <code>EnableEventValidation="false"  ViewStateEncryptionMode="Never" ValidateRequest="false"</code></p>

<p>But, nothing is working for me.</p>
