Apple Confirms iPhone 18 Pro Max Cellular Failures on AT&T
Apple confirmed that a small number of iPhone 18 Pro Max devices running on the AT&T network can experience complete cellular service failures, dropping calls, text messages, and mobile data. Devices affected by this specific issue enter SOS mode and cannot have their network connectivity restored through a software update, requiring hardware replacement instead.
The issue affects devices less than a month after Apple released its 2026 product lineup. While the root cause remains undisclosed by Apple, the glitch is restricted to the iPhone 18 Pro Max paired with AT&T in the United States, leaving other models and carriers unaffected.
How the Service Outage Unfolded Across Networks
The connectivity failure emerged shortly after Apple released the iPhone 18 Pro and Pro Max on September 18. The iPhone 18 Pro lineup introduced iOS 27, new camera hardware, and Apple’s A20 Pro chip. Thousands of users subsequently flooded the Apple Support Community, Reddit, and MacRumors Forums with complaints about losing network access, according to MacRumors. Affected users reported that their devices persistently or intermittently displayed “SOS” in the status bar, cutting off normal communications.
AT&T responded by sending automated text messages to customers warning that some phones might be unable to complete calls, texts, or data requests, including emergency calls to 911.
Conflicting Reports Over Software Updates and Replacements
AT&T instructed customers via text message to immediately install iOS 27.0.1 to resolve the connectivity troubles. However, early reports from users on Reddit and other platforms disputed this claim, noting that updating to iOS 27.0.1 failed to restore cellular service on already-impaired devices, as 9to5Mac reported. According to release notes, the update addressed camera performance and Face ID issues on iPhone 18 Pro models rather than cellular connectivity.
Apple clarified that iOS 27.0.1, released Sept. 28, and a separate AT&T carrier settings update—rolling out over a two-week period starting October 2—are designed to prevent working phones from failing. Apple stated that the two updates together are intended to “help prevent this issue from occurring,” rather than restore service to phones that have already failed. Apple stated that any iPhone 18 Pro Max that has already lost service cannot be revived via software and must be replaced free of charge through Apple Support, AT&T, an Apple Store, or an AT&T retail location.
Modem Hardware Differences
In all other countries, the iPhone 18 Pro Max uses Apple’s in-house C2 modem. The iPhone Duo and the smaller iPhone 18 Pro also use the C2 modem worldwide.
Frequently Asked Questions About the AT&T iPhone 18 Pro Max Outage
Which iPhone 18 Pro Max devices are experiencing cellular failure?
The issue is strictly observed on the iPhone 18 Pro Max using the AT&T network in the United States. The smaller iPhone 18 Pro uses a different modem and is not affected by these specific connectivity losses.
Does iOS 27.0.1 fix phones that have already lost service?
No, Apple confirmed that software updates cannot restore service to a phone that has already failed. Affected customers must contact Apple or AT&T to obtain a replacement device.
How can users check for the AT&T carrier settings update?
Users can manually check for carrier updates by opening Settings > General > About on their device. Apple noted that the automated carrier update can take up to 14 days from October 2 to arrive.
Are emergency 911 calls impacted by the glitch?
AT&T warned in customer alerts that the network failure can disrupt calls, data, text messages, and emergency calls to 911 on affected devices. Users experiencing SOS mode should seek alternative communication methods.