What we know so far: Apple is replacing a small number of iPhone 18 Pro Max devices after some AT&T customers lost cellular service, leaving them unable to make calls, use mobile data or send texts. For Cupertino, the problem is an early test of the software and network support behind its latest flagship phone. The company has moved quickly to distribute updates, but it has not yet disclosed how many devices are affected or why replacement is the only option for those customers.
Customer reports indicate the problem has affected only the iPhone 18 Pro Max on AT&T, and Apple says it has seen the same pattern. The company has released a carrier settings update and iOS 27.0.1 to keep more devices from being affected, but customers whose phones have already lost service will need a device replacement from Apple or AT&T.
In a statement provided to Bloomberg, an Apple spokesperson said: "We have identified an issue affecting a small number of iPhone 18 Pro Max users on the AT&T network that may cause a device to lose service and be unable to make calls."
For people whose phones have lost their connection, Wi-Fi may be the only way to use internet-based services. Without a network connection, the phone cannot reliably handle basic cellular functions.
UPDATE: AT&T finally confirmed to me that the iPhone 18 service/SOS issue is known and being investigated with Apple
by u/GleamingGlider in ATT
Apple is sending out a carrier settings update for AT&T users, which is expected to download automatically over the next 14 days. The company has also advised customers to install any available software updates as soon as possible, including iOS 27.0.1.
Users can check for the carrier update by opening Settings, selecting General and then tapping About. The phone should prompt them if an update is available.
Anyone else getting SOS on iPhone 18 Pro Max?!!!!
by u/Efficient-Ad818 in ATT
Carrier settings are separate from a full iOS update. They let Apple and a wireless carrier change certain network-related settings without requiring customers to install an entirely new version of the operating system. The iOS release gives Apple another way to address software problems that may be connected to the service failure.
The issue has drawn attention because the iPhone 18 Pro Max uses different cellular hardware than the rest of Apple's new phone lineup. In the US, the Pro Max includes a Qualcomm modem, while the other new models, including the smaller iPhone 18 Pro, use Apple's own C2 modem.
iPhone 18 Pro Max SOS
by u/WeezyMelt in ATT
The reports do not establish that Qualcomm's modem caused the problem. The available information shows only that the issue is limited to the iPhone 18 Pro Max on AT&T's network. Still, the hardware difference matters because the affected model is the only new iPhone that uses Qualcomm's modem in the US.
Cellular service depends on more than the modem itself. The phone's operating system, carrier configuration and network connection all have to work together, and a problem in any part of that chain can keep a device from connecting to a carrier or maintaining service once it does.
The iPhone 18 Pro Max starts at $1,299 and went on sale two weeks ago. It is Apple's highest-end standard iPhone, and it arrives ahead of the company's forthcoming foldable iPhone Duo, due October 23.