Apple confirms cellular bug in some AT&T iPhone 18 Pro Max models

Apple has confirmed that a “small number” of iPhone 18 Pro Max devices using AT&T have lost cellular service and cannot make calls, according to a statement to 9to5Mac cited by TechRadar.

The issue affects iPhone 18 Pro Max models on AT&T. The iPhone 18 Pro is not affected, TechRadar reports, likely because it uses a different modem. Affected phones show “SOS” in the status bar and cannot use AT&T’s network for calls, texts or data, though Wi-Fi should continue to work.

Apple is rolling out a carrier settings update intended to prevent the problem on phones that have not already been affected. The update will not fix devices with the bug. TechRadar says it should install automatically within 14 days; users can also check for a prompt under Settings > General > About. Apple’s iOS 27.0.1 update is also intended to prevent the issue.

For phones already affected, TechRadar reports that replacement is the only option. It says Apple Support or AT&T can be contacted by phone or online, or customers can visit an Apple Store or AT&T branch. The report says affected users should receive a free replacement and recommends backing up the current iPhone first.