Twitter users and MacRumors forum members have reported problems, while users who can’t get their phones activated in US Apple stores are being sent to AT&T shops.
There’s been no official word from Apple about the cause of the issue, but Tim Cook and Co are bound to be furious after suffering the same problem at the end of July.
The tech giant is unlikely to comment on the current downtime, after offering no official statement about it last time out.
With the recent hack and temporary closure of its developer site, Apple has suffered a few embarrassing niggles over the past few weeks.
It’ll be hoping that such activation struggles can be sorted ahead of the forthcoming launch of its iPhone 5S and low-cost iPhone 5C, which is certain to lead to a surge in demand for Apple handsets.