My website keeps having this problem when trying to login? please advise me what to do.?

Server Error in '/' Application.

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Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that %26lt;machineKey%26gt; 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 %26lt;machineKey%26gt; configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.

Source Error:

[No relevant source lines]

Source File: App_Web_default.aspx.cdcab7d2.um3t8_ne.0... Line: 0

Stack Trace:

[HttpException (0x80004005): Unable to validate data.]

System.Web.Configuration.MachineKeySecti... buf, Byte[] modifier, Int32 start, Int32 length, Int32%26amp; dataLength) +2646292

System.Web.UI.ObjectStateFormatter.Deser... inputString) +214

[ViewStateException: Invalid viewstate.

Client IP: 65.34.193.236

Port: 4249

User-Agent: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1; .NET CLR 2.0.50727; .NET CLR 1.1.4322)

ViewState: /wEPDwUKLTI3MTEzOTkxMQ9kFgJmD2QWAgIDD2QW...

[HttpException (0x80004005): Validation of viewstate MAC failed. If this application is hosted by a Web Farm or cluster, ensure that %26lt;machineKey%26gt; configuration specifies the same validationKey and validation algorithm. AutoGenerate cannot be used in a cluster.]

System.Web.UI.ViewStateException.ThrowEr... inner, String persistedState, String errorPageMessage, Boolean macValidationError) +116

System.Web.UI.ObjectStateFormatter.Deser... inputString) +251

System.Web.UI.ObjectStateFormatter.Syste... serializedState) +4

System.Web.UI.Util.DeserializeWithAssert... formatter, String serializedState) +37

System.Web.UI.HiddenFieldPageStatePersis... +220

System.Web.UI.Page.LoadPageStateFromPers... +83

System.Web.UI.Page.LoadAllState() +35

System.Web.UI.Page.ProcessRequestMain(Bo... includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +6978

System.Web.UI.Page.ProcessRequest(Boolea... includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +213

System.Web.UI.Page.ProcessRequest() +86

System.Web.UI.Page.ProcessRequestWithNoA... context) +18

System.Web.UI.Page.ProcessRequest(HttpCo... context) +49

ASP.default_aspx.ProcessRequest(HttpCont... context) in App_Web_default.aspx.cdcab7d2.um3t8_ne.0...

System.Web.CallHandlerExecutionStep.Syst... +303

System.Web.HttpApplication.ExecuteStep(I... step, Boolean%26amp; completedSynchronously) +64

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Version Information: Microsoft .NET Framework Version:2.0.50727.832; ASP.NET Version:2.0.50727.832

My website keeps having this problem when trying to login? please advise me what to do.?microsoft publisher

Your using .net framework, That means you need to only use internet explorer to access the page , (Firefox and Safari will NOT Work)

My website keeps having this problem when trying to login? please advise me what to do.?microsoft live internet explorer

Does not look easy. May be you can contact an ASP.NET expert. Check websites like http://oktutorial.com/