Button for my website, and webhook

[Techlosophy]

Just a test to see if I can post to the forum.

[Techlosophy]

OK - sorry for starting this off with a test message - but the community forum rejected my previous 3 attempts to post, so I wanted to make sure I could get a message started before I took the effort to write more.

I'm selling just one thing on my website, so I think a simple payment button should work fine; I think a shopping cart sounds like overkill for my use case. 

I'd like a button to take care of all the payment stuff at PayPal., and then use a webhook to notify my listener of the events (or just certain events).

I have a webhook listener on my webserver that seems to work fine; I can POST to it, and it writes the POSTed information into a log file so I can view it later. It works great when I POST to it. When I try to use PayPal's Webhook Simulator, the response is: 

   Event Status: Your event has been successfully queued at  Wed Sep 20 2023

   Event Data Sent: <JSON data that was sent>

Sadly, none of this makes it to my listener. Does anyone know what tricks are needed to get the Webhook Simulator to work?

I'll try to write this in small chunks (to try to keep the discussion simpler).

Thanks for your help.

[Techlosophy]

Well I continue to fiddle around with webhooks, and I made a few tweaks to my PHP webhook listener., leading to a new discovery: I now see that when I use PayPal's webhook simulator, it ACTUALLY DOES POST to my listener; however the POST just contains no data. Any ideas on how to get the webhook simulator to actually POST some data?????