Trouble setting up iOS Push Notifications (APNS)

The following is caused by an invalid or outdated Provisioning Profile.

• "no valid aps-environment entitlement found for application" (NSError displayed using NSLog)
• "The entitlements specified in your application’s Code Signing Entitlements file do not match those specified in your provisioning profile" (displayed in Organizer window)

Take note that even if you're just updating an existing App ID in the Provisioning Portal, say you've just enabled this app's Push Notifications, you would also need to modify and re-submit the application's current Provisioning Profile (make sure that your test device is included in the list). After that, download and install this file, update Code Signing Identity section of your project's Build Settings to reflect the new profile (in xcode of course), then you're on to the next case.