看来是触发风控了，在和 Apple 客服沟通后已解决。具体方式为：
* 进入 https://getsupport.apple.com/topics
* 选择 iTunes Store
* 选择 Unable to purchase from iTunes Store
* 选择 Chat
我 ：
I am unable to use a gift card to complete my subscription on ChatGPT.
Apple:
I'm sorry to hear about the issue, I'll do my best to get this issue resolved.
Before taking any actions, I will need to verify your identity. I would request you to sign in with your Apple ID using this link : https://appleid.apple.com/account/manage
If prompted, enter the verification code that is sent to your trusted device, or answer your security questions.*
Once done, scroll to the bottom of the screen and click Support PIN. Then click Generate PIN from the pop-up window and share it with me.
我：
**** (你的临时支持 PIN)
Apple:
Thanks.
Allow me a moment to check your account.
我：
在手机上重新订阅，就成功啦。
