Siteniz  “[HttpException (0x80004005): 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.]” hatasini veriyorsa aşagıdaki kodları webconfig dosyanızına entegre etmeniz probleminizi cözücektir. <pagesenableEventValidation=“false“viewStateEncryptionMode =“Never“ />   <system.web> <pagesvalidateRequest=“false“enableEventValidation=“false“enableViewStateMac=“false“viewStateEncryptionMode=“Never“> </system.web> Yada…