Why your push notification didn't arrive: the FCM and APNs errors, and the failures nobody reports

A push notification has two lives. In the first, your server asks Firebase Cloud Messaging (FCM) or Apple's APNs to deliver it, and gets an answer. In the second, a phone somewhere decides whether to show it. Most debugging goes wrong because people read the first answer as if it described the second. This is a guide to both: what the errors from... Weiterlesen: Why your push notification didn't arrive: the FCM and APNs errors, an…