Apple and AT&T have yet to explain the cause of the iPhone 18 Pro Max problem

In a statement shared with Woozad On Friday, Apple said that iPhone 18 Pro Max users who experienced an issue where AT&T cellular service is not working will need to have the device replaced, as the issue apparently cannot be fixed with a software update once it has occurred. This is a big deal because it hints at a hardware failure, but we’re lacking details since Apple and AT&T have yet to disclose the underlying cause of the problem.

An AT&T spokesperson directed us to Apple, which has not yet responded to our latest request for comment. It’s possible that Apple is still investigating the issue, but so far our follow-up questions have been met with radio silence (pun intended).

In the meantime, all we know is that Apple said that iOS 27.0.1 and an AT&T carrier settings update released last week “are intended to prevent this issue from occurring,” so iPhone 18 Pro Max users who haven’t experienced this issue should make sure both of these updates are installed immediately to avoid possible future impacts.

To install iOS 27.0.1, open the Settings app on your iPhone and tap General → Software Update.

The carrier settings update for the iPhone 18 Pro Max will automatically download for AT&T users within the next 14 days, according to Apple. To manually trigger the update, users can open the Settings app and tap General → About.

Apple said it only observed this issue with iPhone 18 Pro Max users on the AT&T network. No other iPhone models or carriers are known to be affected.

Notably, US models of the iPhone 18 Pro Max rely on Qualcomm’s Snapdragon X80 modem for cellular connectivity, while variants of the device sold in all other countries feature Apple’s custom C2 modem. It’s unclear if this modem difference is a factor in this AT&T problem, or if the overlap is just a coincidence.

We have contacted Qualcomm and will share the company’s response, if any.

Apple said a “small number” of iPhone 18 Pro Max users have experienced this AT&T issue, which prevents phone calls, text messages and cellular data from working. A “small number” is Apple’s standard wording for these types of issues. Thousands of users have complained about the issue within the Apple Support Community and on other platforms.