Security Exception - What To Change

[Larry Rebich]

I'm running a very simple web application and get this error. What do I need
to change?
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Security Exception
Description: The application attempted to perform an operation not allowed
by the security policy. To grant this application the required permission
please contact your system administrator or change the application's trust
level in the configuration file.

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I have made the following change in Web.config but it still does not run:

<authorization>

<allow users="*"/>

</authorization>
Larry Rebich