AT&T says it is working with Apple to resolve cellular connectivity problems affecting a small number of iPhone 18 Pro Max devices in the United States. The issue can prevent affected phones from handling calls, texts, mobile data, and 911 calls, with devices often switching into SOS mode.

In a statement, an AT&T spokesperson said Apple had released a software update intended to address the problem and advised customers to install the latest available software. AT&T also said customers who continue to experience connectivity failures can visit an Apple or AT&T store for additional assistance.

What is happening with the iPhone 18 Pro Max?

Since the iPhone 18 Pro Max launched on September 18, affected users have described either persistent or intermittent failures to connect to AT&T’s network. The symptoms include an inability to place calls, send text messages, or use cellular data, followed by the phone displaying SOS mode.

The scale of the issue has drawn reports across Apple’s support community, Reddit, and other online discussion platforms. However, Apple has not publicly identified the cause, and it remains unclear whether the problem is related to hardware, software, or AT&T’s network.

The U.S. iPhone 18 Pro Max is also the only new iPhone model introduced last month that uses a Qualcomm cellular modem. The iPhone 18 Pro and iPhone Duo use Apple’s C2 modem worldwide, while iPhone 18 Pro Max models sold outside the United States also use the C2 modem. There is currently no confirmation that the modem difference is connected to the failures.

Does iOS 27.0.1 fix the problem?

AT&T recently advised some customers to update to iOS 27.0.1. A purported internal AT&T email shared online said the guidance was intended to help mitigate future impacts, but did not clearly explain whether the update resolves existing connectivity failures.

Apple’s release notes for iOS 27.0.1 mention fixes for other problems, including a Face ID issue affecting iPhone 18 Pro models. Affected users have said the update did not appear to restore reliable AT&T service, so its role in addressing this particular issue remains uncertain.

What affected customers can do

Customers experiencing the problem should install the latest available iOS version and contact Apple or AT&T for support. AT&T has said stores can provide additional help, including possible replacement devices, although some customers have reported difficulty obtaining warranty replacements.

For U.S. customers who bought or received an iPhone 18 Pro Max on launch day, October 2 is the final day of Apple’s standard 14-day return period. That deadline may be relevant to customers who cannot rely on their phone’s cellular connection.

Apple may ultimately address the issue with another software release, although the underlying cause has not been confirmed. If the problem proves to be hardware-related, Apple could instead need to establish a repair or replacement program.