TestFlight Subscription Issue: 'Account Not In This Store' Error Despite Correct App Store Region

Question

I am testing subscription purchases through TestFlight and encountering an issue. When attempting to make a purchase, I receive the following error:

Account Not In This Store
Your account is not valid for use in the U.S. store. You must switch to the Pakistani store before purchasing.

My Apple ID is set to the Pakistani region, and my App Store is also configured for the same region. I've confirmed these settings, yet the error persists.

Steps I’ve tried so far:

• Verified that my Apple ID is indeed linked to the Pakistani store.
• Checked my app's settings in App Store Connect to ensure it is available in the correct region.
• Reviewed similar questions on Apple Developer forums, but none provided a clear solution.

Additional Context:

• I am using TestFlight for testing.
• Subscriptions were set up in StoreKit 2.
• The app is being developed for macOS.

Could this issue be related to:

• TestFlight configuration?
• Incorrect product region availability in App Store Connect?
• Something I missed during subscription setup?

Any insights or troubleshooting steps would be greatly appreciated.