Apple confirmed that a bug in the iPhone 18 Pro Max on AT&T causes devices to lose cellular service, requiring affected users to swap their phones for new units. The issue, which affects handsets sold in the United States, prevents phone calls, texts, and data use.
Cellular connection troubles have hit a subset of iPhone 18 Pro Max devices running on the AT&T network.
“We have identified an issue affecting a small number of iPhone 18 Pro Max users on the AT&T network that may cause a device to lose service and be unable to make calls.”
Apple spokesperson, via Bloomberg News
The $1,299 phone, which went on sale two weeks ago, serves as Apple’s highest-end handset outside of its forthcoming foldable, the iPhone Duo. While the total number of impacted customers remains unclear, owners have reported spotty connection troubles and devices getting stuck in data-less SOS mode since the initial launch. AT&T previously sent out text alerts warning customers about potential connection disruptions that could hinder emergency service calls.
Hardware Replacement Required for Disconnected AT&T Users
Software patches cannot restore cellular capability once a device loses connection. Apple said that iPhone 18 Pro Max devices that have been affected by this cellular issue on the network cannot have service reactivated with a software update. Instead, devices must be swapped out entirely.
Customers experiencing these disruptions are finding their handsets largely unusable unless connected to Wi-Fi networks. Affected users should reach out to customer support at Apple or AT&T, depending on where they purchased their hardware. Shoppers can also visit an Apple Store or AT&T retail location to receive assistance and secure a replacement.
Software Updates and Qualcomm Modem Speculation
While swaps are necessary for disconnected phones, Apple has deployed preventative updates to shield unaffected users. The company released iOS operating system version 27.0.1 and an AT&T carrier settings update designed to keep the glitch from spreading.
The carrier settings patch will automatically roll out to AT&T devices over the next 14 days, though Apple strongly encouraged all iPhone 18 Pro Max users to update to iOS 27.0.1 now. Users can trigger the software installation manually through the device settings menu.
Industry observers have pointed to hardware architecture as a potential culprit. The U.S. version of the iPhone 18 Pro Max differs from other models by incorporating a standalone cellular modem manufactured by Qualcomm Inc. All other variants in the lineup, including the smaller iPhone 18 Pro and non-U.S. Max units, rely on Apple’s in-house C2 modem. Neither Apple nor AT&T has officially confirmed whether this modem distinction directly caused the glitch.
