title: Facebbok read_insights permission doesn't seem to work for the ad account
body: <p>I can't get insights information from ad account.
  I am admin of both ad account and application.</p>
  
  <p>In the Graph API Explorer all fields under insights are grayed out.
  It seems like access token doesn't have read_insights permission, but It does. I can see all the permissions in the Access Token Debugger under Scopes: read_insights, manage_pages, ads_read, public_profile</p>
  
  <p>ads_read permission works just fine.</p>