Apple and AT&T have not yet identified the root cause of connectivity issues affecting some iPhone 18 Pro Max devices on the AT&T network. Affected users report an inability to make calls, send texts, or access mobile data, with some devices entering SOS mode.
Apple stated that software updates cannot restore service to devices that have already lost connection. The company released iOS 27.0.1 and an AT&T carrier settings update intended to prevent the issue on other devices, rather than repairing those already impacted. Affected units require a full hardware replacement.
The problem is currently limited to the iPhone 18 Pro Max paired with AT&T. While US models utilize the Qualcomm Snapdragon X80 modem and international versions use Apple's proprietary C2 modem, Apple has not confirmed if these hardware differences are linked to the failure.
Users who have not yet experienced the issue are advised to install iOS 27.0.1 and the latest carrier settings. Those already facing connectivity loss should contact Apple or AT&T directly to arrange for a device replacement.
