Hey @kyin-3899ff,
Unfortunately, Apple’s Sandbox environment is notoriously flaky - sometimes purchases can get hung up in their system, where most of the time this error is due to sandbox downtime, but you can read about all the causes for this error in our guide on error handling here: https://docs.revenuecat.com/docs/errors#--store_problem - when reviewing, this is the used environment too, which can cause issues when the reviewer tests in-app purchases like subscriptions.
I would recommend re-submitting your app for review (some developers have submitted the same binary up to a dozen times before getting through). Just to clarify, there's nothing you as a developer or RevenueCat can do to resolve these errors except retrying later/resubmitting.
One thing it helps, is to send a note to the reviewer with some instructions on how to get to the product/paywall purchase and ask for them to review the in-app purchases/subscriptions in advance too.
The good news is that Apple uses a separate production environment that is much more stable for live purchases, and these issues aren’t often seen in the same manner as in the sandbox environment. Additionally, this typically only happens when an app is being launched for the first time- subsequent updates typically work as expected for the reviewer.
Lastly, we have a great blogpost article going over all the environments, in case you haven’t come across it, which adds some extra context in each.
Let us know how this process goes and if the app gets approved or the rejection message is different.
