FAQs

Q1. Why do push notifications experience a drop?

A drop in push tokens happens due to:

1. Token not passed to the HCL CDP SDK: Incorrect implementation prevents the token from being sent to the SDK.
2. Push notification access not granted: Users select "Don't allow" when prompted for push notification permissions.
3. Network connectivity issues: Poor or no internet connection on the device disrupts token updates.

Solutions:

• Ensure correct implementation of push notification in your app. Confirm that your app registers successfully for push notifications and generates a device token, which must be sent to the SDK.
• Send a test campaign to the target device to verify functionality.
• If the test campaign succeeds but no notification appears, check the app's notification settings on the device.

Q2. Why are push notifications not deliverable?

Push notifications fail to deliver for the following reasons:

1. Notifications blocked at the OS level: Users disable app notifications, or battery-saving features stop apps from running in the background.
2. Device-specific issues: Some devices block notifications when the app isn’t active. Manufacturers are gradually resolving this.
3. Network issues: Notifications fail when users have no internet connection or FCM (Firebase Cloud Messaging) can’t maintain a stable connection.
4. TTL expiration: Notifications expire if the device doesn’t connect to FCM within the set Time-to-Live (TTL) period.
5. Token inactivity gap: If a user uninstalls the app, there’s a delay before FCM marks the token inactive, leading to undeliverable notifications.

Q3. Why are some push notifications queued?

Notifications queue up due to:

• Do Not Disturb (DND) mode: Devices delay delivery until DND mode is turned off.
• Frequency caps: Notifications aren’t sent if users exceed the configured daily, weekly, or monthly limit.

Q4. What is a Silent Push Notification?

Silent push notifications update apps in the background without alerting the user. These are used to fetch updates or perform specific tasks.

In HCL CDP, silent push notifications are employed to track app uninstalls. Devices that fail to receive these notifications are marked as uninstalled.

Q5. Why might push notifications fail to deliver?

• Frequency Caps: Notifications don’t deliver if the user exceeds the frequency limit set for daily, weekly, or monthly messages. For more information about Frequency Caps, refer here.
• Personalization Failure: Notifications fail when user profiles lack the required parameters for personalized content. Suppose a user belongs to a segment without a registered premium amount. If you create an engagement for that segment using a premium amount macro with an expiration date, the user does not receive the engagement because their profile lacks the required parameter.
• FCM Failure: Delivery fails due to Firebase Cloud Messaging (FCM) errors.
• FCM/APNS Configuration Issues: Mis-configured app settings, missing APNS certificates, or incorrect FCM setup can block notification delivery.
• Unsubscribed Users: Users who opt out of notifications won’t receive them.
• Network Issues: Poor internet connectivity on the user’s device prevents delivery.
• DND Mode: Notifications are delayed or missed when devices are in Do Not Disturb mode.
• OEM Restrictions: Some device manufacturers, especially Chinese OEMs, implement battery-saving features that restrict background notifications.
• App Uninstalled: Notifications can’t be delivered to users who uninstall the app.
• Other Issues: System failures, server crashes, or campaign errors may also disrupt delivery.