Web Portal Installation HTTP Error 500.19 - Internal Server Error

I am building a sandbox installation of OID 8.1.2 in a vm with Windows Server 2019 and SQL Server 2019.

I set up the IIS with Windows Authentication and enabled this for the default web site, then installed the Web Portal using the OID installer. When I completed and tried to access the site, I get the error below. I can't see any missing configuration steps in the installation documentation, so I'm hopeful someone can help me. Thanks in advance.


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

Notification
BeginRequest

Handler
Not yet determined

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".

Config File
\\?\C:\inetpub\wwwroot\IdentityManager\web.config

Requested URL
win-p4qhdt0pf93:80/.../

Physical Path
C:\inetpub\wwwroot\IdentityManager\

Logon Method
Not yet determined

Logon User
Not yet determined


Config Source:
155: <system.webServer>
156: <handlers>
157: <add name="page.axd_GET,POST" path="page.axd" verb="GET,POST" type="VI.WebRuntime.Communication.WebPageFactory, VI.WebRuntime" />