@tasunil,
404 not found means that your client library does not exist.
Assuming that you are working on the author as your local development environment, you are logged in as an administrator, accessing /etc.clientlibs/* should not be a problem at all with authentication.
The first thing that caught my eye is, does the client library exist in the JCR? In CRX/DE can you find and resolve, /apps/settings/wcm/designs/social/console/resources.css or /libs/settings/wcm/designs/social/console/resources.css. And is this resource a valid client library?
Secondly, once you locate the resources that generate the client library CSS & JS files, copy the clientlib category. Now, double check if the client library is valid using dumplibs tool, localhost:4502/libs/granite/ui/content/dumplibs.html.