Apple confirmed Friday that a small number of iPhone 18 Pro Max owners on AT&T have lost cellular service and can't make calls, though thousands have complained on Apple's support forums and elsewhere. iOS 27.0.1 and AT&T carrier settings update 72.1 are meant to stop it happening to more phones. Apple told 9to5Mac that the updates won't restore a phone that has already lost service and that those owners will need a hardware replacement, through Apple Support, AT&T or a store.
Apple hasn't said what causes it. U.S. models of the iPhone 18 Pro Max use Qualcomm's Snapdragon X85 modem and every other country gets Apple's own C2, though it is not yet clear that mattered. Apple Stores sound ready to replace affected phones for free, according to MacRumors. Owners have said 27.0.1 didn't help, and AT&T's own text to customers warned that some phones may be unable to complete calls, including to 911.