A subset of iPhone 18 Pro Max users in the U.S. are experiencing issues with AT&T cellular connectivity and/or eSIM provisioning, according to complains across the MacRumors Forums, Reddit, and the Apple Support Community. Affected users are unable to connect to the AT&T network for phone calls, text messages, or data. Notably, the U.S. version of the iPhone 18 Pro Max is the only new iPhone released this month that is equipped with a Qualcomm cellular modem.