suddenly this error started appearing when I am running my web application, I have a GridView control, with editing enabled, once i click on the "edit" button on the gridview I get this error message:
"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. "
I hope someone could help.
thanks in advance.