These push notifications require a valid SIM card and an active internet/cellular connection.
Please note that delivery of notifications is controlled entirely by Apple's Push Notification Service (APNS), and CallHippo has no way to resolve issues with this service. If we send you missed call notification while you are offline. That notification will be sent to APNS to be delivered to your phone. CallHippo has no control or visibility over the delivery of these notifications. The issue may be presenting itself in CallHippo, but the issue derives from APNS or the iOS.
Please refer to solution article by WhatsApp- https://faq.whatsapp.com/iphone/20950116 for more info.
While we try to figure out a workaround. We recommend you to turn ON Call forwarding so that you don’t miss a call while you are away from the network.
If you have any questions. Please feel free to reach out to us at support@callhippo.com