Initial Reports
Late last week, issues affecting cellular connectivity for AT&T versions of Apple's newest iPhone 18 Pro Max were reported.
Unfortunately, in an update from Apple, users might need to replace an affected iPhone 18 Pro Max at an Apple Store or AT&T store.
Issue Details
Brand-new Pro Max phones were starting in SOS mode and not connecting to AT&T's network, or they were operating slowly when they did connect. AT&T acknowledged the problem and stated that the carrier was working with Apple on it.
Our top priority is ensuring customers can stay connected when they need it most, and we are working with Apple to make it right, an AT&T spokesperson said.
At the time, both Apple and AT&T were encouraging iPhone 18 Pro Max owners to update to iOS 27.0.1, which was meant to fix the issue.
We released iOS 27.0.1 earlier this week and strongly encourage all iPhone 18 Pro Max users to update now, and are also issuing a carrier settings update today, an Apple spokesperson stated. These updates together are meant to help prevent this issue from occurring.
Hardware Replacement Required
However, if you already have an affected device without service, it cannot be reactivated via software. Apple confirmed that users will need to go to an Apple or AT&T store to get a hardware replacement.
This issue has only been observed with the iPhone 18 Pro Max on the AT&T network.
Potential Cause
Notably, the US version of the Pro Max is the only new iPhone that utilizes a Qualcomm cellular modem, while the Pro model and iPhone Duo feature Apple's in-house-designed C2 modem. However, it's unclear whether the modem difference is causing the problems, since no other carrier appears to be affected.
