Hello, I have created webhooks previously with another store which are still working fine. I simply copied over the code in the PHP file (and changed the "SHOPIFY_APP_SECRET") to test the webhook. I created the webhook in the new shopify store and pointed it to the correct URL for the new PHP file.
When I test the webhook, it is not doing anything. I have tested the actual code, and it works on its own.
I have also simplified the code right down to the basics, and also all the way down to: