Delivery issues with push notifications can usually be determined by examining the responses from APNs.
APNs will return useful information both in the HTTP/2 header response, and as a JSON dictionary for unsuccessful requests. You can find the list of responses, and further troubleshooting steps in the article Handling Notification Responses from APNs:
If the above document does not help clarify the issue, or issues with receiving notifications persist despite receiving an error status neither in the HTTP/2 headers nor in the response JSON dictionary, we may be able to assist you with diagnosing the issue.
If you are using a third-party push notification provider service, we recommend to contact them first to make sure the issue is not between your app and their service, and to obtain information on any errors they might be receiving from Apple servers.
To help diagnose the issue, we will need some information about the push requests. Please include the following information in your post, for a failed or delayed notification that has been attempted within the last 48 hours:
The following are required to start a diagnosis:
- Exact time and date (including time zone) of the push request sent
- Exact time and date (including time zone) of the notification received by the device (if received at all)
- Your app’s Bundle ID
- The token the push was sent to
- The returned (error) status and message from APNs
- Full contents of the HTTP/2 headers
- Full contents of the payload
The following are helpful for timely and accurate diagnosis of the issue:
- If using your own server to send: the public IPv4 address of the push provider server used to send the push
- If using a third-party service to send: the name of the third-party push provider service used
- The push topic (apns-topic header value)
- The push type (alert, background, VoIP, other)
- The apns-id (either set in your request, or received from the HTTP/2 header response)
- Any logging you have from the server side that shows the interaction with it and APNs
If you are using a third-party push provider service, and do not have the above necessary info, or only have the info you are providing to the service, please first contact the service provider for a resolution or to give you the above specific information.
When posting about an issue you are having with sending/receiving push notifications, include the above required information and as much of the secondary helpful information you can collect with your post in an organized manner for us to be able to help with diagnosing the issues.