IAP prompts DuplicateTransaction

Unity 2019.4.12f1
IAP 2.1.1
iOS phone

The ios account is in the subscription period, but the user has cancelled the subscription. Try to purchase the subscription again, iOS prompts that the purchase is successful, but IAP prompts DuplicateTransaction

After that, I restarted the application. After IAP initialization was completed, I received a prompt that IAP resumed the purchase and was successful. Because I am using a sandbox test environment, I am not sure if the previous subscription period has expired.

I now want to know how the client should operate when IAP prompts DuplicateTransaction, or how to avoid this situation？

Thank very much

 

First,The user purchased a continuous renewal product for appB on the iOS account userA

Second,The user canceled the continuous renewal before the renewal time was reached

Then,The user purchases a continuous renewal again (via the subscription button in the app)

iOS prompts that the purchase is successful, but IAP prompts DuplicateTransaction

 

I still get the same error after updating

 

@JeffDUnity3D
Sorry, I can only see error log 'DuplicateTransaction' form function

Code (CSharp):

1. public void OnPurchaseFailed(Product product, PurchaseFailureReason reason)

in my class

Code (CSharp):

1. public class MyStoreListener : IStoreListener

I use iOS14.5, I can cancel the subscription in the Setting->App Store->SANDBOX ACCOUNT->Manage, and then use another game account in the app to purchase subscription products. You can see this error message. I hope you can reproduce it and help explain the problem.

Thank you very much

 

use another game account means have to use IAP function 'InitiatePurchase' to purchase product.Not resume purchase.

If I do not cancel the subscription, iOS will not call up the payment process.
iOS will prompt me that I have already purchased this subscription

If you still have not reproduced it, please provide the specific steps of your operation and explain the results of each step.

Thank you very much

 

@JeffDUnity3D
Sorry for not responding in time in recent days
But, I think the steps I provided before are already very clear. I checked my steps again and I think there is nothing to add.

The following steps use the same sandbox account and the same app.All payments are for continuously renewing products purchased.
First,The user purchased a continuous renewal subscription product for an app use sandbox count.
Second,The user canceled the continuous renewal subscription( in the Setting->App Store->SANDBOX ACCOUNT->Manage on iOS14.5) before the renewal time was reached
Then,The user purchases a continuous renewal subscription again(via the subscription button in the app), At this time the app is still within the subscription period

iOS will evoke the payment interface,then iOS prompts that the purchase is successful, but IAP prompts DuplicateTransaction

For me, There will be problems with my steps.

Do you mean that did not operate my steps or did not pass my steps to reach a conclusion?

If you use the made with Unity app installed on your iOS phone through my steps or through the steps you understand, then there must be steps for you to operate. For example, use Unity2019.4.12f1, IAP3.1.0 to build an iOS application, and then purchase continuous subscription products through the purchase button in the application, and then cancel the subscription in the iOS settings, and then...
I just want to use the steps you have implemented to confirm what deviations have occurred in the steps I described

For me, I have to use another game account to see the purchase button in my app, because I used the first game account to purchase a subscription, and the subscription has not expired, so there will be no purchase button in the app.
As long as you can purchase subscription products again through the app, you can ignore using another game account.

I hope you must follow my steps to reproduce the problem I encountered.
This question is very critical for us, it determines whether we can get revenue through subscription. Also determines the robustness of Unity payment.

Thank you very much

 

@JeffDUnity3D
For developers, I can clearly see the Restore purchase recommendations on the iOS and IAP documents.
But our designer does not consider adding a Restore purchase button on our app.
Even if we add the button to Restore purchase, if the user cancels the subscription and switches the game account, there is no subscription information on the game account, but the user forgets that he has subscribed to this application or operated by the user’s family, and the user tries to purchase the subscription product again. Because IAP’s error callbacks have caused us to give users a very bad experience.
For our testers, they try all possible payment methods as much as possible, but we do not consider the possible operations of this kind of users. As developers, we are extremely irresponsible to the testers and users.

Therefore, it is not recommended for this, but the user can trigger the operation. Is the DuplicateTransaction returned by IAP correct? Or you are still struggling to restore purchase?

Fear that you will forget the steps to reproduce again

The following steps use the same sandbox account and the same app.All payments are for continuously renewing products purchased.
First,The user purchased a continuous renewal subscription product for an app use sandbox count.
Second,The user canceled the continuous renewal subscription( in the Setting->App Store->SANDBOX ACCOUNT->Manage on iOS14.5) before the renewal time was reached
Then,The user purchases a continuous renewal subscription again(via the subscription button in the app), At this time the app is still within the subscription period

iOS will evoke the payment interface,then iOS prompts that the purchase is successful, but IAP prompts DuplicateTransaction

Thank you very much