看起来Apple的记录很差。基本上，您不应该从该屏幕登录沙盒用户。在测试IAP实际提示时登录。

来源：无法使用设备上的沙盒测试用户登录

I have an app in the App Store and I want to test in-app purchases. I followed the steps described on the Apple website but I'm facing some problems.

When I try to log in in the iTunes in my application or in Settings/iTunes & App Stores, I receive the error:

iTunes account creation not allowed.

This Apple ID cannot be used with the iTunes Store at this time. Please try again later

I searched the internet but I found nothing about this. It seems like I am the first to encounter this kind of error.

Looks like Apple has this poorly documented. Basically, you shouldn't log in with your sandbox user from that screen. Log in when actually prompted by your test IAP.

Source: Unable to log in with sandbox test users on device