Server Error in '/' Application, Length cannot be less than zero. Parameter name: length

[Yugioh017]

Can someone help me with this problem when im tring to load a page and
error pops up, if you can solve this problem thank you alot , so if
you manage to fix it then email me, thank you for your time.

Server Error in '/' Application.
--------------------------------------------------------------------------------

Length cannot be less than zero. Parameter name: length
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.ArgumentOutOfRangeException: Length cannot
be less than zero. Parameter name: length

Source Error:

An unhandled exception was generated during the execution of the
current web request. Information regarding the origin and location of
the exception can be identified using the exception stack trace
below.

Stack Trace:


[ArgumentOutOfRangeException: Length cannot be less than zero.
Parameter name: length]
System.String.Substring(Int32 startIndex, Int32 length) +172
Passport.Web.Security.Identity.DecryptAuthCookie(HttpCookie
authCookie) +329
Passport.Web.Security.Identity..ctor(HttpContext context) +101
Passport.Web.Site.Global.Application_AuthenticateRequest(Object
sender, EventArgs e) +29
System.Web.SyncEventExecutionStep.System.Web.HttpApplication
+IExecutionStep.Execute() +60
System.Web.HttpApplication.ExecuteStep(IExecutionStep step,
Boolean& completedSynchronously) +87