Some iPhone 18 Pro Max users in the United States are reporting problems with AT&T cellular service, including failed connections for calls, text messages, and mobile data. Reports also describe difficulties provisioning eSIMs, according to user discussions on Reddit and the Apple Support Community.

The issue appears to affect only a subset of owners rather than every iPhone 18 Pro Max customer using AT&T. The reports do not establish a single cause, and neither Apple nor AT&T has been identified as having publicly confirmed the scope of the problem.

What AT&T customers are experiencing

Affected users say their devices are unable to connect to the AT&T network. Depending on the case, that can prevent normal phone calls, SMS messages, and cellular data from working. Other reports focus on eSIM provisioning, which can stop a mobile plan from being activated or transferred successfully.

The complaints have appeared across multiple user forums, including an Apple Support Community discussion and a Reddit thread focused on iPhone 18 Pro Max devices showing an SOS status on AT&T. Because these are user reports, they do not confirm how widespread the issue is or whether all affected phones share the same technical problem.

Why the U.S. iPhone 18 Pro Max is different

The U.S. version of the iPhone 18 Pro Max is the only new iPhone released this month that uses a Qualcomm cellular modem. The smaller iPhone 18 Pro and the iPhone Duo use Apple’s C2 modem worldwide. The iPhone 18 Pro Max also uses the C2 modem in markets outside the United States.

That hardware difference has raised the possibility that the modem configuration could be involved in the AT&T problems. However, there is currently no confirmation that the Qualcomm modem is responsible, and the available reports do not prove a hardware connection.

Possible iOS 27.0.1 fix

Apple is testing iOS 27.0.1, which is expected to arrive next week. The update may include a carrier update intended to resolve the AT&T connectivity and eSIM issues, although Apple has not confirmed that the release will address this specific problem.

Until more information is available, the reports point to a developing compatibility or provisioning issue affecting some U.S. iPhone 18 Pro Max owners on AT&T. The rollout of iOS 27.0.1 should provide a clearer indication of whether software changes can restore service.