I'm calling RedeemAppleAppStoreInventoryItemsRequest to validate IAPs on iOS, passing in the receipt and entity key.
Testing these purchases in a sandbox environment, my initial purchase received a successful response from the API call. However, after this initial try I keep getting a failure response:
"FailureCode":"Unknown", "FailureDetails":"Failed to redeem offer [productId]. Please try again later."
The odd thing is that the item request actually succeeds and adds the item to the player's inventory in the PlayFab backend, but returns a failure response.
Checking the transaction history for the player, everything looks fine and the item is successfully redeemed. Additionally, this error doesn't occur on Android using RedeemGooglePlayInventoryItemsRequest.
Retrying the request with the same receipt multiple times in a row returns the exact same failure response.
Do you know what could be causing this call to return a failure response despite actually succeeding?