HTTP Error 500.19 - Internal Server Error: The requested page cannot be accessed because the related configuration data for the page is invalid.

Module IIS Web Core
Notification BeginRequest
Handler Not yet determined
Error Code 0×80070021
Config Error This configuration section cannot be used at this path. 
             This happens when the section is locked at a parent level.
             Locking is either by default (overrideModeDefault=”Deny”), 
             or set explicitly by a location tag with overrideMode=”Deny” 
             or the legacy allowOverride=”false”.
Config File \\?\C:\wwwroot\yoursite.com\web.config