Hello!
A bit late response on this one.
But, here are 2 main things:
First, there are a few steps that are up to the developer or user to make push notifications work.
Read the “Remarks” section in the documentation of Push notifications here
Second, we have a bug in the way this works in Appfarm. Give this scenario: The app is added to home screen (installed PWA) and requests permissions, and the user says “Deny”. Then, the user goes to the notification center on the phone, and allows permissions. With this flow, the “Appfarm server” does not know about the subscription, and will not send notifications to that user/device. Workaround: Uninstall PWA, reinstall, request permissions (and accept). Or if you have the same issue in the browser: Reset permissions, then request permissions.
…and then, there is the issue of iOS 17.4.