Web Applications HTTP error 500.19 - This configuration section cannot be used at this path.
Issue
Opening the PME web application in a web browser yields the following error.
Product
Power Monitoring Expert 9.x
Power Monitoring Expert 2020
Power Monitoring Expert 2021
Power Monitoring Expert 2022
Power Monitoring Expert 2023
Power Monitoring Expert 2024
Environment
Web Application
Windows OS
Recent installed Software
Cause
This issue is typically related to IIS/.NET feature configuration or IIS configuration locking that prevents PME web components from compiling/serving correctly.
Primary cause (most common)
- One or more required IIS > Application Development features are not installed or not enabled (e.g., ASP.NET 4.8, .NET Extensibility 4.8, ISAPI Extensions/Filters). This often occurs after Windows updates, IIS re‑installation/repair, or server rebuilds where roles/features revert to defaults.
Configuration locking indicators
- The error states the section is “locked at a parent level.” This is usually enforced by:
- Server‑level policy such as
overrideModeDefault="Deny" - A
<location>tag withoverrideMode="Deny" - Legacy behavior with
allowOverride="false"
- Server‑level policy such as
Why this can happen
- The server was hardened (for example):
- Security baselines / corporate hardening templates
- Group Policy changes affecting IIS configuration
Context clues (system otherwise healthy)
- Devices are connected in Management Console; Vista is displaying real‑time values.
- Only the web layer (IIS handlers/modules/config) is impacted.
- The web app previously worked and stopped after OS/IIS changes (patching, repair/reinstall, recovery/restore, or manual edits to
applicationHost.config/siteweb.config).
Note
- Missing IIS/.NET components can break PME Web Applications even when PME services and databases are functioning normally.
Resolution
If using Windows 7 or 8, open the Start menu and type "Turn Windows features on or off" into the search bar.
In the features window, open Internet Information Services > World Wide Web Services > Application Development Features
Enable all features and close the window.
If using Windows Server 2012, open Server Manager, then click Manage > Add roles and features.
Click next, then select the PME Server in the Server Selection window and click Next.
In the Server Roles window, expand Web Server (IIS) > Web Server > Application Development.
Ensure that the latest .NET and ASP.NET features are selected, as well as CGI, ISAPI Extensions and Filters, and Server Side Includes are selected.
The following command may unlock that part of the file for all virtual roots:
(Generic command): Do not run the command as-is, make changes where necessary.
The following command will unlock this section globally.
%windir%\system32\inetsrv\appcmd.exe unlock config -section:system.webServer/security/requestFiltering
If you only want unlock it for a particular site/app, you can do
%windir%\system32\inetsrv\appcmd.exe unlock config "SiteName/app/url" -section:system.webServer/security/requestFiltering
Example
For System DataService:
%windir%\system32\inetsrv\appcmd unlock config -section:system.webServer/modules
Note
After doing the procedure outlined in this KB, the Web Application may return a new error - HTTP Error 500.21. Click the following link to find a solution: Error 500.21 SOLUTION
Recommendation:
If you are using an older version of PME, consider upgrading to the latest version for improved protocol support and security. For assistance with integration or upgrades, contact Schneider Electric Technical Support at: pmo.support@se.com
Released for: Schneider Electric Canada
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