Your iPhone 18 Pro Max can do a lot. It has a variable aperture that lets you control the amount of light that hits the camera sensor; it can charge up to 50% of its battery in 15 minutes (with the right adapter, of course); and it can run all of Apple’s latest AI features, thanks to the new A20 processor. But the 18 Pro Max is still, above all, a phone. If it can’t connect to the cellular network, you no longer have an iPhone, but a glorified iPod touch.
Unfortunately, that’s the situation some iPhone 18 Pro Max users find themselves in. Despite being “the best” iPhone Apple has ever made, Apple confirmed that a “small number” of 18 Pro Max units—specifically on the AT&T carrier network—can no longer connect to cellular service, with the devices only displaying an “SOS” icon at the top of their screens. That’s a pretty glaring issue: Without cellular service, you’ll need a wifi connection to use any apps or features that require the internet and you’ll lose the ability to make calls over cellular entirely. It’s so bad that some users may not even be able to call 911.
What if my iPhone 18 Pro Max can connect to cellular service right now?
If your iPhone 18 Pro Max has the ability to connect to cellular service, that doesn’t mean you’re in the clear. Just because there’s nothing wrong with your unit yet, you can still be affected by the glitch, and you’ll need to install the latest update, iOS 27.0.1, as well as the latest carrier update from AT&T, to ensure your 18 Pro Max won’t be affected by these mysterious cellular issues in the future. That’s what Apple told 9to5Mac in the following statement: “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. 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. These updates together are meant to help prevent this issue from occurring.”
While you can always install iOS 27.0.1 from Settings > General> Software Update, Apple says that the carrier update will install on its own at some point over the next 14 days. However, I’d advise manually installing it by heading to Settings > General > About. There won’t be any confirmation that the carrier update installs, but rest assured, this process will ensure that it has.
What if my iPhone 18 Pro Max cannot connect to cellular?
Unfortunately, if your iPhone is already experiencing issues connecting to cellular service, there is no fix. The updates above only help with prevention; they cannot patch an iPhone 18 Pro Max that already can’t reach the network. Unfortunately, the only solution is to swap out the unit with either Apple or AT&T. The good news is your store will make the trade for you free of charge, as it is a hardware defect covered under warranty.
It’s not clear why this issue is only affecting iPhone 18 Pro Maxes and not the standard iPhone 18 Pro, nor is it evident why only AT&T devices appear to be experiencing it. A possible point of failure: The iPhone 18 Pro Max uses a Qualcomm modem, while the iPhone 18 Pro uses Apple’s proprietary C2 modem. Perhaps there’s some flaw with Qualcomm’s hardware specifically on the AT&T network.
That’s not to say the launch of the iPhone 18 Pro has been otherwise drama-free—far from it. As it happens, the 18 Pro (along with the 18 Pro Max) has also experienced three other public-facing issues since Apple launched the devices last month. First, there was an issue with phones randomly rebooting following a failed Face ID attempt; next, some users noticed their devices emitting a cracking or popping sound through the speakers. Finally, some units also appear to be losing their exterior color. If you’ve upgraded, I hope your fancy new iPhone is doing well.