Embedding SAML Application

I have created a SAML integration application that is IdP initiated. If i go to dashboard, i am able to login to the app without any problem. But when I embed the app URL in an iframe, i get authenticated but as if no SAML response is posted as my application (on there service provider) display a login page instead of loggin me in directly. As i said it works fine when do it outside of iframe

Anything i am missing?