Resolved : HTTP Error 500.21 – Internal Server Error Handler “PageHandlerFactory-Integrated” has a bad module “ManagedPipelineHandler” in its module list

You’ll get error when you run your website from IIS 7 it’ll give you error 500.21 with following details.

Caution :
you .net framework is not registered with IIS..

Solution:

Register your .NET Framework with IIS using following command.

%windir%\Microsoft.NET\Framework\v4.0.21006\aspnet_regiis.exe -i

if you are having x64 system. it’s following syntax

%windir%\Microsoft.NET\Framework64\v4.0.30319\aspnet_regiis.exe -i

or

Start
->All Programs
-> Microsoft Visual Studio 2010
->Visual Studio Tools
-> Visual Sutdio Command Prompt(2010)

->Right Click on the Visual Studio Command Prompt (2010)
->select Run as Administrator incase of Windows 7 and Vista

then apply aspnet_regiis.exe -i