Urgent : Live Application In App Purchase Subscription Issue - Unknown error. Please contact support

### Platform

- [Y] iOS
- [ ] macOS
- [ ] tvOS

### In app purchase type

- [ ] Consumable
- [ ] Non-consumable
- [Y] Auto-Renewable Subscription
- [ ] Non-Renewing Subscription

### Environment

- [ ] Sandbox
- [Y] Production

### Version
ℹ Please replace this with the version of SwiftyStoreKit you're using.
0.13.3

### Related issues
ℹ Please replace this with references to similar issues (either open or already closed).
https://github.com/bizz84/SwiftyStoreKit/issues/376

## Report

### Issue summary
ℹ Please replace this with an explanation of the issue, including reproduction steps.
We are using SwiftyStoreKit GitHub library for In App Purchase subscription. It's working fine. Some user is reporting that they are not able to purchase due to purchaseProduct returns: Unknown error.

### What did you expect to happen
ℹ Please replace this with what you expected to happen.
It should subscribe.

### What happened instead
ℹ Please replace this with what happened instead.
It's retuning message with below message :
Unknown error. Please contact support