In-App purchase fails but system dialog say you're all set

### Platform

iOS 12.1

### Device

iPhone 6 (real device, not simulator)

### In app purchase type

Auto-Renewable Subscription

### Environment

Sandbox

### Report

Since a few hours I am unable to test my in-app purchases:

1. When executing the purchase option, the system will receive messages that the purchase has been completed ("You are all set. Your purchase was successful"). In fact the error occurs "Cannot connect to iTunes Store". The problem came suddenly, old app versions that worked before also have this bug. I suspect the bug is caused by apple.

Error Domain=SKErrorDomain Code=0 “Cannot connect to iTunes Store"

enum value = SKErrorUnknown

Note: A few hours ago I immediately received the message that the connection to iTunes is not possible. Without the success system messages.
https://developer.apple.com/system-status/ indicates that there are no erros
At the moment: some people on twitter and stackOverflow are also indicating that they have this problem.

### Steps tried

1. Deleted app
2. Logout from app store
3. Restarted Phone
4. Deleted sandbox user on itunes connect
5. Created new sandbox user on itunes connect
6. Installed app
7. Entered sandbox credentials
8. Executed in-app purchase
9. Error still occours