Not able to handle connectyucube in iOS during kill state

We are using connectycube library in react native for video calling but we are not able to connect video call during kill state in iOS. To handle this we are using VOIP push notification in IOS and we are using call keep library but in some cases video call is working fine and sometime not, also if my app is in kill state and someone is calling me then if I reject the call then caller end it is not rejecting. Also same thing is happening for Android as well.

We tried to handle through firebase push notification but it was not helpful because in kill state we are not able to handle firebase data.

Reference
https://developers.connectycube.com/reactnative/videocalling

Please someone provide any solution for this so that we can resolve this issue.