I've made Apple in-app-subscriptions. And it works successfully. And then I try to work with promotional codes, but it doesn't work.
If I understood correctly, I have to use this method:
import * as RNIap from 'react-native-iap';
...
RNIap.presentCodeRedemptionSheetIOS();
This code opens a request window. And when I enter the correct code, a message appears with the text "You must enter a valid code."
Works fine now. I just created promo codes in the wrong place.
Here is the doc: https://help.apple.com/app-store-connect/#/dev6a098e4b1