Sandeep, your comments tell you what the issue is:

"but when I click the post, I am rediretcing to my portal and asking to login to see the content as its a private profile"

If you want to share something on Facebook, the content has be set to PUBLIC in the visibility/privacy settings of the content. Facebook does not have a way of logging into your site and getting images, albums, videos, etc. So it may post the 'link' but it will not post any content.