I'm using a Flutter project and RevenueCat for payment processing, but both of my projects are experiencing subscription failures. The SDK is showing the following error message:
E/[Purchases] - ERROR(): 🤖‼️ Error when fetching products - DebugMessage: Billing Unavailable. ErrorCode: BILLING_UNAVAILABLE.
E/[Purchases] - ERROR(): 🤖‼️ PurchasesError(code=PurchaseNotAllowedError, underlyingErrorMessage=Error when fetching products - DebugMessage: Billing Unavailable. ErrorCode: BILLING_UNAVAILABLE., message='The device or user is not allowed to make the purchase.')
E/[Purchases] - ERROR(): 🤖‼️ Error fetching offerings - PurchasesError(code=PurchaseNotAllowedError, underlyingErrorMessage=Error when fetching products
I used a real machine to run it, and my APK was also released on Google Play's internal testing platform. I tried it on different machines and logged into different Google accounts.
I've checked the forums and seen similar issues before, but there weren't any correct solutions. I'm very anxious and hope someone can help me.

