How to take permission for creating contacts group?

Question

I want to create contact group for user. I am using oauth 2.0. I have added 'https://www.google.com/m8/feeds' scope also.

Below is my code.

contactService.setAuthSubToken("access Token");

But i am getting below exception.

<p>Your client does not have permission to get URL <code>/m8/feeds/groups/[email protected]/full</code> from this server.
<ins>That&#39;s all we know.</ins></p>