IIS 8 windows 2012 shib sp request maphandler issue 404

[C G]

Deeply appreciate if someone can give me some pointers on getting maphandler invoked --
IIS 8 server on windows 2012
Current status : shib sp loads 
Shibd -check gives the config loadable

The protected page access takes us to Idp and after authentication the SAML2/POST ends up in wrong handler 

Gives 404 error with URL hostname:443/Shibboleth.sso/saml2/post 
Is getting mapped to physical path c:\inetpub\shibboleth.sso\saml2\post

The module is IIS web core (instead of Shibboleth) and the error is 0x800700002 
On maprequesthandler 

Cross checked isapi filters, handler mapping, 
Unchecked request restrictions, allow all verbs and allow script Both at server and site level:

Shib logs are clean -- only warning we see is cookieprops is set insecure, set it to ssl/tls 


In IIS logs we hostname/Idp/profile/saml2/redirect/SSO;jsessionid=xxxx?execution=e1s1&eventid_proceed=1 404 0 2 358

What am I missing? Appreciate if any one can share their troubleshooting playbook

By 127.0.0.1/shibboleth.sso/status gives 404 error as the mapping is not working....

Thanks in advance!!!