Handler "AutowiredPageHandlerFactory" has a bad module "ManagedPipelineHandler" in its module list error on IIS

I tried to install Sitecore Horizon on my local machine. After running the PowerShell script, after some execution. I resolved that error but somehow my working instance was stopped and I got the below error when I hit the website in the browser.

I tried to uninstall Horizon but no luck. Before starting installation, I took the backup of my root so I reverted my root folder but still my original instance was not working. After some googling, I found the solution. Please refer to the below details for more information.

Error type: HTTP Error 500.21 - Internal Server Error

Please follow the below steps if you are facing same issues in your instance.

• Open Application Pools of your website root.

  



• Right-click on the application pool of your website and select the Advance setting.

  



• Now select .Net CLR Version from “No managed code” to “v4.0”.

• Open command prompt as a run as administrator and run “iisreset” command.

• Now website will start working fine.