You need to get your phone replaced if it has already lost its signal.
After a number of complaints about network issues affecting iPhone 18 Pro Max devices, Apple has now confirmed that there is indeed a problem. It appears that the issue has only affected AT&T users in the US, and an iOS update is already available to fix it. That said, the update won’t work for those already affected by the problem. They need a hardware replacement, Apple said 9 on 5Mc.
What Apple is saying about the AT&T issue
It is not difficult to tell if your phone has the error. If this is the case, your iPhone 18 Pro Max will show the “SOS” symbol in the status bar instead of signal bars. Calls, text messages and data over 4G or 5G will also stop. The good news is that not every iPhone 18 Pro Max owner using AT&T was affected. Apple says it only affects a “small number” of users, and it has 9 on 5Mc 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 encourage all iPhone 18 Pro Max users to update now, and are also issuing a carrier settings update today.
Interestingly, the iPhone 18 Pro Max is the only model sold in the US that uses a Qualcomm modem instead of Apple’s own – but it’s not clear if there’s a direct connection between that and the bug. If you’ve checked the boxes to get an iPhone 18 Pro Max with an AT&T SIM card, here’s what to do. First, update to iOS 27.0.1 as soon as possible. Just give up Settings > General > Software Update and check for the latest version.
If you’ve already updated, it’s also worth checking to see if you have the latest carrier settings. Also Settingsgo to General tap About to trigger the update. If you don’t see a pop-up about a carrier settings update, you probably already have the latest version. Unfortunately, if your iPhone has already lost its cellular signal, a software update or restore won’t work. You should contact Apple Support or AT&T to request a phone replacement instead.