I found this error installing for the first time in a certain server the IIS tools, specially the WCF feature.
The detailed error is:
HTTP Error 500.19 – Internal Server Error
The requested page cannot be accessed because the related configuration data for the page is invalid.
Detailed Error Information:
Module IIS Web Core
Error Code 0x80070021
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”.
The solution is simple: to unlock IIS configuration for module settings, enter the following commands in an elevated PowerShell context.
Import-Module WebAdministration Set-WebConfiguration ` -Filter "/System.webServer/modules" ` -Metadata overrideMode ` -Value Allow ` -PSPath "IIS:\"