At a glance: Configure your Facebook account to support events postback from Cost Center for ROAS campaigns.
1. Log in to https://business.facebook.com/
2. Go to Users > People > Select the user who authorised is with Cost Center
3. Click Add Assets > Apps > Select your app > Toggle on permission "Test app"
4. Go back to Cost Center > Data Connectors > Facebook connector > Click on the "Refresh" icon
5. Go to Events Postback > Facebook: your Facebook App should appear in the dropdown.