HTTP Error 500.21-internal Server error handler "Pagehandlerfactory-integr" has an error module in its module list Managedpipelineh

The Web site was published to IIS, and the access error occurred as follows:

HTTP Error 500.21-internal Server error handler "Pagehandlerfactory-integr" has an error module "Managedpipelinehandler" in its module list

Cause: After you install the framework v4.0, then enable IIS, causing the framework not to be fully installed

Resolve: Start-> All Programs-> attachment-> Right click "Command Prompt"-> Run as Administrator-> input

%windir%\microsoft.net\framework\v4.0.30319\aspnet_regiis.exe-i

If not, check the application pool for IIS, use Integrated mode, or if not, change to Integrated mode