1. Ensure that you have an Admin or Editor role on the page - see this Facebook help page for more information. If you have another type of role on the page, CrushNinja filters out the page because you do not have sufficient permissions to publish content.
  2. Due to Facebook's Granular Permissions system, it is now possible for users to grant app permissions on a per-page basis. The most likely explanation is that CrushNinja was not granted permissions for the page you wish to manage. To fix this, go to Settings -> Business Integrations on Facebook, remove/deauthorize the CrushNinja app, and then log in to the CrushNinja website again, making sure to grant CrushNinja access to all of your pages. The page should now appear under the "Unmanaged Pages" tab of CrushNinja and be available for management.