iPhone 18 Pro Max AT&T Cellular Issue: Apple Says Replace Device

The AT&T Cellular Issue on iPhone 18 Pro Max

Apple has confirmed that a "small number" of iPhone 18 Pro Max users on the AT&T network ran into a serious problem: their devices lost cellular service entirely. When that happens, phone calls, text messages, and data all stop working, leaving the phone unable to do the basics on a cellular connection.

Even though Apple describes the affected group as small, the reports were anything but quiet. Thousands of users complained about the issue across the Apple Support Community and other platforms, suggesting the problem was far more visible than the official characterization might imply.

According to Apple's statement, the company "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 also noted that it has only observed this issue with iPhone 18 Pro Max users on the AT&T network, and that no other iPhone models or carriers are known to be impacted.

Apple's Fix: iOS 27.0.1 and AT&T Carrier Settings Update

Apple has moved quickly to contain the problem. The company released iOS 27.0.1 earlier this week and pushed out an AT&T carrier settings update earlier today, with both updates intended to help prevent more iPhone 18 Pro Max users from being impacted going forward.

In a statement shared with MacRumors, Apple strongly encouraged all iPhone 18 Pro Max users to update to iOS 27.0.1 now. To install it, open the Settings app and tap General → Software Update.

The carrier settings update works a little differently. According to Apple, it will automatically download for AT&T users over the next 14 days. Those who would rather not wait can manually trigger it by opening the Settings app and tapping General → About.

Apple's full statement explains that the two updates together "are meant to help prevent this issue from occurring." For anyone who has not yet lost service, installing both is the simplest way to reduce the risk of joining the thousands of users who have already reported problems.

Affected Devices Must Be Replaced, Not Fixed by Software

For iPhone 18 Pro Max users whose devices have already lost cellular service on AT&T, the newly released software is not a cure. Apple confirmed that affected devices "cannot have service reactivated with a software update." Instead, the device must be replaced entirely.

Apple advises affected customers to contact Apple Support or AT&T, or to visit an Apple Store or an AT&T location to arrange a replacement. According to MacRumors, Apple Stores will replace affected iPhone 18 Pro Max devices for free, so booking a Genius Bar appointment may be the fastest route.

It remains unclear whether Apple will eventually launch a dedicated Apple Service Program for this issue. Until then, anyone whose iPhone 18 Pro Max has already lost service on AT&T should treat the iOS 27.0.1 and carrier settings updates as preventive measures only, and pursue a hardware replacement rather than waiting for a future fix.

Scope, Cause, and Modem Differences

According to Apple, the issue has only been observed with iPhone 18 Pro Max users on the AT&T network. No other iPhone models or carriers are known to be impacted.

Apple did not disclose the underlying cause of the issue, leaving questions about why this combination of device and network is affected.

One notable difference is the modem inside the iPhone 18 Pro Max. U.S. models rely on Qualcomm's Snapdragon X80 modem for cellular connectivity, while variants of the device sold in all other countries are equipped with Apple's custom C2 modem. It is unclear if this modem difference is a factor in this AT&T issue.

It is also unclear if there will eventually be an Apple Service Program dedicated to this issue. In the meantime, it sounds like Apple Stores will replace affected iPhone 18 Pro Max devices for free, so book an appointment with the Genius Bar if necessary.