I got this from App Store review:
We noticed that your app did not meet all the terms and conditions for auto-renewing subscriptions, as specified in Schedule 2, section 3.8(b) of the Paid Applications agreement.
We were unable to find the following required information in your app's binary:
– Length of subscription (time period and content or services provided during each subscription period)
I use Flutter to build my iOS app. Could that be why Apple can't find the information in my binary?