This article explains a limitation of IIS Web Agent.
Release : 12.52
Component : SITEMINDER -WEB AGENT FOR IIS
If you add a Virtual Directory which points to the same directory as the Default Web Site recursively, Web Agent Configuration is done but accessing the URL of the Virtual Directory fails.
Furthermore, an error will be observed when clicking its CASiteMinderWebagentModule or Handler Mappings in IIS Manager, such as following.
Error: Cannot add duplicate collection entry of type 'add' with unique key attribute 'name' set to 'CASiteMinderWebagentModule'
Do not add such a recursive Virtual Directory.