My app unlocks certain abilities to users that have purchased a subscription. The app is built on Unity and it implements the Unity IAP service (which works great with both Google Play and Apple). The issue I have encountered is when I attempt to implement the Amazon store. The store works and the user can purchase the subscription but when he reopens the app it does not receive the subscription he already owns. In short: the Amazon IAP does not restore the purchases automatically.
I know that apple has a restore purchases issue that needs to be called by the code and my question is how can I do this with Amazon? Is it supposed to be restored automatically?
I implemented Amazon IAP using the Amazon SDK, and not via Unity IAP, I know that it should support restoring purchases.
During init, you can get a list of purchases and their status, and there's a particular status indicating that the purchase was made but not fulfilled; you can then ask the Amazon store to fulfill the purchase, hence restoring it.
I did not work with Unity IAP, but did you look into this manual page ?https://docs.unity3d.com/Manual/UnityIAPRestoringTransactions.html