pages public content access requires either app secret proof or an app token facebook api code example
Example: (#100) pages public content access requires either app secret proof or an app token
There is a changes in the facebook scope new scopes instead of manage_pages
and page_insights :
--------------------------------------------------------------------------
<fb:login-button size="large" scope="public_profile,email,pages_show_list,
read_insights,pages_read_user_content,pages_read_engagement,
pages_manage_metadata,pages_manage_ads" onlogin="checkLoginState();">
Click here to sync
</fb:login-button>