Apple Confirms Cellular Issue Affecting Some iPhone 18 Pro Max Units on AT&T
Apple has confirmed a cellular connectivity issue affecting a limited number of iPhone 18 Pro Max devices on AT&T in the United States, saying units that have already lost service require hardware replacement rather than a software fix.
iPhone 18 Pro Max Cellular Failure
The issue has caused some affected phones to enter “SOS” mode, preventing users from making calls, sending text messages and accessing cellular data. For some users, the problem remained even after installing iOS 27.0.1.
Apple said iOS 27.0.1, along with a separate carrier settings update, is designed to prevent the issue from occurring on devices that have not yet been affected. However, the updates cannot restore cellular service to phones that have already lost connectivity.
Affected Phones Require Hardware Replacement
Devices that have lost cellular service require hardware components to be replaced. Affected users can contact Apple or AT&T support, or visit an Apple Store or AT&T location for assistance.
AT&T has warned that the issue may prevent some phones from making calls, sending messages and connecting to cellular data, including emergency calls to 911.
Qualcomm Modem Used in U.S. Models
The issue is linked to the U.S. version of the iPhone 18 Pro Max, which uses a Qualcomm cellular modem. The iPhone 18 Pro and iPhone Duo use Apple’s C2 modem globally, while iPhone 18 Pro Max models sold outside the United States also use Apple’s modem.
Apple has not identified the modem as the cause of the problem, and there is currently no confirmed evidence that Qualcomm components are directly responsible.