There is a SharePoint hosted add-in (app) installed from Office Store, which uses standard Office Store licensing (and API for license validation).
SharePoint Online portal has some external users (like described here).
External users have "edit" rights on site where add-in (app) is deployed. They can see the add-in (app) in Site Contents and even open some configuration pages for the add-in (app) where license is not validated.
When external user tries to open the add-in (app) he receives message that he does not have valid license for the add-in (app).
When I go to
Office 365\Administrator\ADMIN\SharePoint\Apps\Manage licenses and try to include the external user to add-in (app) license the user can not be picked.
Is is possible to add external user to add-in (app) license?