See why you can’t advertise for certain Pages or apps in Ads Manager and Power Editor- If you are attempting to advertise for a specific Facebook Page or app and it’s not available for selection, you may lack the proper Business Manager permissions.
See This: Facebook Login
This can happen if:
You do not have advertising permissions for the app or Page you want to advertise for.
To get advertising permissions in Business Manager, request it from your Business Manager admin.
Your ad account was not approved to advertise this app or Page when you first created it.
To advertise for an app or Page you already have user permissions for in Business Manager, create a