Messages do not fire when the app is in the background.

[kwg105]

While onMessage always works, onResume never fires for me while the app is in the background.

[vuitv]

i too have same issues

[krongnang]

@vuitv @kwg105 any update?

[x401om]

Hey guys! I suppose you faced the limitation:

Important

On iOS 13.0 and later, if you fail to report a call to CallKit, the system will terminate your app. Repeatedly failing to report calls may cause the system to stop delivering any more VoIP push notifications to your app. If you want to initiate a VoIP call without using CallKit, register for push notifications using the User Notifications framework instead of PushKit. For more information, see User Notifications.

https://developer.apple.com/documentation/pushkit/pkpushregistrydelegate/2875784-pushregistry

When I faced this issue, I was able to solve just reinstalling the app. Also you need to report a call to CallKit. Read this #2 issue for more details