同样的事情发生在我身上，因为在iOS 11发布之前创建了三个独立的沙盒用户。 （这个问题在iOS 11上似乎很流行，reddit和苹果论坛上的帖子报道了这个问题）

The same thing happens for me, for three separate sandbox users which were created before iOS 11 release. (The problem seems prevalent on iOS 11, there are posts on reddit and apple forums reporting this issue)

似乎创建新的沙盒用户是可行的方法。在iOS 11发布后工作时创建的沙盒用户，而在发布之前创建的沙盒用户会导致登录/创建Apple ID警报循环。

It seems creating new fresh sandbox user is the way to go. Sandbox users created after iOS 11 release work, while those created before the release cause "Sign in/Create Apple id" alert loop.