1604 Views 3 Replies Latest reply: Jun 24, 2010 8:36 AM by skylily881
Copied from this link.
Apple Push Notification Service requires iPhone OS 3.0 or later and a connection to the Internet, either via a cellular data network or Wi-Fi, and at least one application that supports notifications.
If the device is connected over Wi-Fi and is still unable to receive notifications, the Wi-Fi network you're using might have a firewall that is blocking port 5223. This port must be open to TCP traffic for notifications to work.