I keep getting an error page.
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.
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.
Source Error:
[No relevant source lines]
Source File: c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary
ASP.NET Files\root\10d0a9a5\9c4a911b\App_Web_qmosheqv.3.cs Line: 0
Stack Trace:
[HttpException (0x80004005): Unable to validate data.]
System.Web.Configuration.MachineKeySection.GetDecodedData(Byte[] buf, Byte[] modifier, Int32 start, Int32 length, Int32& dataLength) +289
System.Web.UI.ObjectStateFormatter.Deserialize(String inputString) +140
[ViewStateException: Invalid viewstate.
Client IP: 212.22.186.170
Port: 1108
User-Agent: Opera/9.80 (Windows NT 5.1; U; en) Presto/2.2.15 Version/10.10
ViewState: 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...]
[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.]
System.Web.UI.ViewStateException.ThrowError(Exception inner, String persistedState, String errorPageMessage, Boolean macValidationError) +106
System.Web.UI.ViewStateException.ThrowMacValidationError(Exception inner, String persistedState) +14
System.Web.UI.ObjectStateFormatter.Deserialize(String inputString) +242
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() +105
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.index_aspx.ProcessRequest(HttpContext context) in c:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary
ASP.NET Files\root\10d0a9a5\9c4a911b\App_Web_qmosheqv.3.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:2.0.50727.3607;
ASP.NET Version:2.0.50727.3082