Try this: <key>NSAppTransportSecurity</key> <dict>     <key>NSAllowsLocalNetworking</key>     <true/> </dict>

Hi everyone! I've got the same error (SKError.Code.unknown, i.e. 0) and underlying message. It appears when a client tries to purchase the same product second time. It looks like this case shouldn't happen, because if all set correct, client shouldn't generate purchase second time. But I guess, it is easy to reproduce it having second device for the same appleId and initiating second purchase. Ways to reproduce: Client chooses product item AppStore shows message that such product has been purchased and is still active SKPaymentTransactionObserver gets error: SKError.Code.unknown with underlying message (as noticed in initial message of this thread) So, client knows what happened and transaction observer too. It is helpful for transaction observer as we can disable spinner on product items screen (for example), but what about other cases when we get such .unknown error code and other underlying messages? Should we show "Unknown message happened" to a client or just react on it silently, without client notification, and restoring purchases in a background? Can developers rely on such underlying messages? What's the goal of such error code? Thanks in advance.

As it described here "In-App Purchase FAQ", "Localization" section https://developer.apple.com/library/archive/technotes/tn2413/_index.html#//apple_ref/doc/uid/DTS40016228 it is necessary to sign in to App Store Connect https://appstoreconnect.apple.com using your test account. I've made it through Safari, using my test account, and got error related to necessity to be part of the team to sign in - but it doesn't matter. After that you can open you app and see that IAP products got correct localization. Problem solved

In my case it was necessary to add WatchKit Extension to WatchKit App target - General - Frameworks, Libraries and Embedded Content WatchKit App target - Build Phases - Dependencies

In my case a cause of the problem was second structure created with a name of existed structure, but located in a different group folder. It is weird, but XCode didn't provided an appropriate description on that problem. Cache cleans didn't help. The problem was localised after the first build run where structure names duplication was outlined.

I've met the same problem working on iOS Custom Notification Extension. The problem has appeared after trying to add App Group for this extension. I've got the message: Provisioning profile "iOS Team Provisioning Profile: myXXXXXXXExtension" doesn't match the entitlements file's value for the com.apple.security.application-groups entitlement. I've checked the entitlements file definition - it had correct definition of the group I've tried to add. After reading response of @nwpeakbagger in this thread I've checked "Bundle Identifier" value in Info.plist of this module. This value was absent as well as "Bundle display name" I've defined values for these attributes: "Bundle Identifier" = $(PRODUCT_BUNDLE_IDENTIFIER) "Bundle display name" = myXXXXXXXExtension The problem has been solved. Many thanks to @nwpeakbagger and Apple Dev Community!