I am getting this error in my aspx page, can anyone plz provide me solution for this..

Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Web.HttpException: Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that <machineKey> configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

Hi
You can use this Code on WEB.COFIG file

<pages theme="test" validateRequest="false" enableEventValidation="false" viewStateEncryptionMode="Never">

I hope you its useful for you to avoid that Error