While working in portal I am facing the problem of server error within every 15 – 20 minutes. The message I am getting is mentioned below. Please look into this matter ASAP.
Server Error in '/' Application.
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.
http://go.microsoft.com/fwlink/?LinkID=314055
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.
http://go.microsoft.com/fwlink/?LinkID=314055
Source Error:
[No relevant source lines]
Source File: App_Web_ykmjvje5.12.cs Line: 0
Stack Trace:
[ViewStateException: Invalid viewstate.
Client IP: 122.163.48.2
Port: 13894
User-Agent: Mozilla/5.0 (Windows NT 5.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.116 Safari/537.36
ViewState: 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
Referer: http://www.rtnetwork.i...]
[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.
http://go.microsoft.com/fwlink/?LinkID=314055]
System.Web.UI.ViewStateException.ThrowError(Exception inner, String persistedState, String errorPageMessage, Boolean macValidationError) +153
System.Web.UI.ViewStateException.ThrowMacValidationError(Exception inner, String persistedState) +14
System.Web.UI.ObjectStateFormatter.Deserialize(String inputString) +237
System.Web.UI.ObjectStateFormatter.System.Web.UI.IStateFormatter.Deserialize(String serializedState) +4
System.Web.UI.Util.DeserializeWithAssert(IStateFormatter formatter, String serializedState) +37
System.Web.UI.HiddenFieldPageStatePersister.Load() +207
System.Web.UI.Page.LoadPageStateFromPersistenceMedium() +199
System.Web.UI.Page.LoadAllState() +43
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +6785
System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +242
System.Web.UI.Page.ProcessRequest() +80
System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) +21
System.Web.UI.Page.ProcessRequest(HttpContext context) +49
ASP.stateadmindashboard_aspx.ProcessRequest(HttpContext context) in App_Web_ykmjvje5.12.cs:0
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +181
System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75
Version Information: Microsoft .NET Framework Version:2.0.50727.4247; ASP.NET Version:2.0.50727.4248