Reasons why an iPhone user may not receive a push notification
There are a few common reasons that a user may not receive a push notification, or where the push notification delivery may be delayed:
- The user may not have a cellular data connection. Also, if more then one push notification was sent while the user’s device was offline then only the latest one will be delivered once data connectivity is restored.
- WiFi network firewalls may block access to TPC port 5223 which is used by the push notification service
- When connected via WiFi, push notifications may be delayed compared to a user connected by a cellular data connection. When connected to WiFi the iPhone will periodically check for new notifications (usually every 15 minutes), in contrast to a cellular data connection which is persistent.
- The user may not have given the app permission in the device settings to receive push notifications