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

Error Message

After installing the IIS Web Adaptor, the configuration page displays the error:

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

Cause

The application pool that the Web Adaptor is assigned to is configured to use .NET Framework version 4.0, but the Web Adaptor requires version 2.0.

Solution or Workaround

1. Open IIS Manager.
2. Select the Application Pools node in the tree view.
3. In the list of Application Pools, right-click ArcGISWebAdaptorAppPool and click Advanced Settings.

4. Change the .NET Framework Version property to be v2.0.

5. Click OK.
6. Reload the Web Adaptor configuration page.