App crashes once the google play billing completed the payment success in flutter

Question

From the Flutter user interface i calls the Google play billing, it's open up the payment screen, and once the payment is done successful. The google play screen has to redirect to the screen where it is initiated to retrieve the response of the payment and need to unlock the features as well to navigate to the respective screens. But unfortunately the app crashes once the payment done successful, and it redirects to the landing screen. Hence even the payment done successful i am unable to provide premium feature to the user. I done this with flutter using getX used in_app_purchase package. could anyone support me to fix this issue will be more helpful