Handler "dotless" has a bad module "ManagedPipelineHandler" in its module list

Question

When I want to use dotless (http://www.dotlesscss.org/) I have a problem:

When I try to request file http://localhost/static/css/StyleLess.less I am receiving a HTTP error:

Handler "dotless" has a bad module "ManagedPipelineHandler" in its module list.

• MVC 4
• asp.net 4.0
• IIS 7 classic mode

However, if application pool is set as "Integrated" I don't have problem.

I've tried to use, among others

• How to get rid of this error Handler "PageHandlerFactory-Integrated" has a bad module "ManagedPipelineHandler" in its module list
• How to fix: Handler "PageHandlerFactory-Integrated" has a bad module "ManagedPipelineHandler" in its module list

with no success

Answer 1

Change of App Pool mode from Classic to Integrated helped me and solved that problem.