If your binary was rejected by Apple, the IAP products submitted with it should also appear as rejected. When you try to purchase a rejected IAP in the application, the aforementioned “You want to buy one unknown application ...” appears on the confirmation screen.
To fix this, you can make a small change for each IAP product in iTunes Connect. Then just change it, then the rejected flag should disappear (and be replaced by waiting for review ). For example, I added 's' to the Display Name for the English language of each product, and then came back and removed the 's'.
This may not be acceptable to Apple if the reason for your rejection is centered around your use of in-app purchases.
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