If you're running into issues when provisioning an instance of Facebook Leads Ads with webhooks, try these steps.
- Ensure that your Facebook app permissions include manage_pages and leads_retrieval.
- On provision, enter the app version that correlates with your Facebook app version.
- When going through the authentication flow for Facebook, make sure to only allow pages that you want to receive events from.
- Make sure you have admin access to those pages: https://www.facebook.com/help/187316341316631?helpref=uf_permalink