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Server Error in '/' Application.

The state information is invalid for this page and might be corrupted.

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: The state information is invalid for this page and might be corrupted.

Source Error: 

[No relevant source lines]

Source File: c:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\vs\aa3cabe8\cc76c9ee\App_Web_lrsncq1a.28.cs    Line: 0 

Stack Trace: 

[FormatException: The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters. ]
   System.Convert.FromBase64_Decode(Char* startInputPtr, Int32 inputLength, Byte* startDestPtr, Int32 destLength) +12703819
   System.Convert.FromBase64CharPtr(Char* inputPtr, Int32 inputLength) +130
   System.Convert.FromBase64String(String s) +42
   System.Web.UI.ObjectStateFormatter.Deserialize(String inputString, Purpose purpose) +66
   System.Web.UI.ObjectStateFormatter.System.Web.UI.IStateFormatter2.Deserialize(String serializedState, Purpose purpose) +13
   System.Web.UI.Util.DeserializeWithAssert(IStateFormatter2 formatter, String serializedState, Purpose purpose) +40
   System.Web.UI.HiddenFieldPageStatePersister.Load() +127

[ViewStateException: Invalid viewstate. 
	Client IP: ::1
	Port: 5654
	Referer: http://localhost:1324/adminefs/Tproducttest.aspx
	Path: /adminefs/Tproducttest.aspx
	User-Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:69.0) Gecko/20100101 Firefox/69.0
	ViewState: 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...]

[HttpException (0x80004005): The state information is invalid for this page and might be corrupted.]
   System.Web.UI.ViewStateException.ThrowError(Exception inner, String persistedState, String errorPageMessage, Boolean macValidationError) +116
   System.Web.UI.HiddenFieldPageStatePersister.Load() +266
   System.Web.UI.Page.LoadPageStateFromPersistenceMedium() +251
   System.Web.UI.Page.LoadAllState() +36
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +6569
   System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +245
   System.Web.UI.Page.ProcessRequest() +72
   System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context) +22
   System.Web.UI.Page.ProcessRequest(HttpContext context) +58
   ASP.adminefs_tproducttest_aspx.ProcessRequest(HttpContext context) in c:\Windows\Microsoft.NET\Framework\v4.0.30319\Temporary ASP.NET Files\vs\aa3cabe8\cc76c9ee\App_Web_lrsncq1a.28.cs:0
   System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +188
   System.Web.HttpApplication.ExecuteStepImpl(IExecutionStep step) +48
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +71

Version Information: Microsoft .NET Framework Version:4.0.30319; ASP.NET Version:4.7.3062.0




توی web.config