Some U.S. iPhone 18 Pro Max devices tied to AT&T have experienced an unexpected service outage, and Apple says software will not bring already-affected phones back online. Apple confirmed to 9to5Mac on Oct. 2 that devices that have already lost service require hardware replacement. AT&T said the affected functions include not only calls, text messages and mobile data, but also 911 emergency calling.
For now, the issue appears concentrated in the United States among AT&T-linked iPhone 18 Pro Max devices. Apple described the affected group as a “small number” of users, without giving a figure.
User reports built up over about a week
Roughly a week passed between the first forum complaints and the formal statements from Apple and AT&T. Posts on the Apple Support Community, Reddit’s r/ATT thread and the MacRumors forums described a similar pattern: phones could not connect to the AT&T network, calls, texts and mobile data stopped working, the status bar showed only “SOS,” and some users said eSIM activation also failed.
Timeline of the incident
- Sept. 18: iPhone 18 Pro and iPhone 18 Pro Max went on sale.
- Sept. 25: outage reports from U.S. AT&T users began appearing on Apple forums, Reddit and the MacRumors forums.
- Late September: Apple released iOS 27.0.1.
- Oct. 1: AT&T sent text messages to users telling them to update to iOS 27.0.1 immediately.
- Oct. 2: AT&T issued a formal statement, and Apple confirmed the issue and its response to 9to5Mac.
AT&T said: “Apple has released a software update to address an issue that may affect a small number of iPhone 18 Pro Max devices with calling, data, messaging and 911 emergency calling. AT&T customers with an iPhone 18 Pro Max should update to the latest software immediately. Our top priority is making sure customers stay connected when they need it most, and we are working with Apple to make this right.”
Update is for prevention; already-failed devices must be replaced
Apple’s response has two parts. The first is prevention. Apple said iOS 27.0.1 was released earlier this week and that it “strongly recommends” all iPhone 18 Pro Max users install it right away, along with a carrier settings update. Taken together, Apple said, those updates are intended to help prevent the issue from happening. The carrier settings update will be pushed automatically within 14 days, and users who want to trigger it manually can go to Settings > General > About.
The second part is remediation. For devices that have already lost service, the software update will not restore connectivity. Those units need hardware replacement. Users can contact Apple Support or AT&T, or visit an Apple Store or an AT&T retail location.
Attention turns to the modem, but Apple has not named the cause
The modem quickly became a focus of outside discussion. The U.S. version of the iPhone 18 Pro Max uses Qualcomm’s Snapdragon X80 and is the only model in this year’s iPhone lineup to use a Qualcomm modem. The international version of the iPhone 18 Pro Max, including Taiwan, and the iPhone 18 Pro use Apple’s in-house C2 modem.
Apple has not said the problem is related to the Qualcomm modem, and it has not disclosed the root cause. There have also been no similar reports involving other carriers. What is confirmed so far is narrower: the issue has appeared on the U.S. model, on AT&T’s network, and Apple has determined that affected devices need hardware replacement.
No similar reports in Taiwan so far
For readers in Taiwan, AT&T is a U.S. carrier, and the Taiwan version uses the C2 modem. No similar cases have been reported there so far. The original report noted that this reflects the current situation, not a guarantee. People who bought a phone in the U.S., or obtained a U.S. model through parallel import channels, may want to check which modem version their device uses and which carrier it is connected to, while keeping both iOS and carrier settings up to date.