I am experiencing an issue while integrating Facebook Webhooks with my server. Here's the behavior I'm observing:

• My app has the following permissions: pages_manage_metadata, ads_management, pages_show_list, pages_manage_ads, pages_read_engagement, leads_retrieval.

• When subscribing to the "Page" webhook, my server correctly receives a GET request for verification from Facebook.

• However, when subscribing to the "leadgen" webhook and running the 'Test' function, my server does not receive the POST request.

• I also tested using the form at: https://developers.facebook.com/tools/lead-ads-testing/, but again, no POST request is received by my server.

• When I send a POST manually to my server using Insomnia, everything works as expected, with the server logging the request and responding with a 200 status.

So, the server is configured to receive POST requests, but they are not being sent from Facebook Webhooks.

Why is my server receiving a GET request from Facebook, but not receiving the POST request, even though it works correctly with a manual POST test via Insomnia?