Ionic Cordova IOS submission SKPaymentTransactionObserver

I have added an In App Purchase plugin on my ionic project and l am able to list the consumable products from my App Store Connect and the Sand box l can buy products working well.

The problem l am facing is that when l submitted my build to app store connect i have an warning the app must support SKPaymentTransactionObserver.

I am not sure what that is at all all my research to setup the In App Purchase i did not come across SKPaymentTransactionObserver.

I would appreciate it if someone can point me in the right direction to submit my app on the store.