I'm facing an issue delivering VoIP push notifications to user devices. It's pretty random, sometimes notifications are delivered and sometimes not. I've had a call with the user to understand and narrow down the issue, including testing delivery of pushes to their device token via Push Notification Console as described here: https://developer.apple.com/documentation/usernotifications/testing-notifications-using-the-push-notification-console#4181180.
I asked a user to use Wi-Fi first and tried delivering around 10 pushes via console and 2 of them were lost while the rest was delivered.
I asked a user to use cellular and tried delivering also around 10 pushes and most of them were lost and only few of them were delivered.
Production environment was used to deliver pushes hence I cannot see delivery log and so I have no visibility over a reason why push wasn't delivered.
I wanted to file a code-level support ticket to get help however I need to supply a sample xcode project which in this particular case doesn't make any sense as I'm using Apple's Push Notification Console tool and it delivers pushes in some cases while doesn't deliver it in other cases.
I'm pretty familiar with all potential reasons why push might not be shown on device, including app early crashes, not reporting a call to CallKit etc. => although you never know, I'm pretty sure it's not our case.
How can I get support on investigating specific user device token delivery issues like in the case I described above? I have device token and push console records but it's not clear how to get support on that.
Thank you!
