Some US iPhone 18 Pro Max owners report AT&T cellular and eSIM failures

A subset of U.S. iPhone 18 Pro Max owners are reporting that they cannot connect to AT&T for phone calls, text messages, or cellular data — and some describe eSIM provisioning failures — according to complaints across the MacRumors Forums, Reddit, and the Apple Support Community, MacRumors reports.

AppleInsider separately said a small number of iPhone 18 Pro and Pro Max users on AT&T are seeing cellular calls fail, with signal strength fluctuating or stuck on SOS only, while Wi‑Fi Calling may still work. The outlet said AT&T has acknowledged some cases tied to eSIMs; Apple has not publicly confirmed the issue.

Modem context — unclear if related

MacRumors notes that the U.S. iPhone 18 Pro Max is the only new iPhone this cycle with a Qualcomm cellular modem. The smaller iPhone 18 Pro and iPhone Duo use Apple’s C2 modem worldwide, as does the Pro Max outside the U.S. Whether that hardware split is a contributing factor remains unclear — neither Apple nor AT&T has attributed the reports to a modem defect.

That regional modem split aligns with our earlier look at four Pro Max hardware versions (SIM, mmWave, modem, battery).

Possible software path — not confirmed

Apple is testing iOS 27.0.1, expected next week. MacRumors said the update may include a carrier update that could help, but there is no confirmation that 27.0.1 fixes these AT&T connectivity reports.

Separately, AT&T’s decision not to support iOS 27 iPhone Handoff is a different topic and should not be confused with these cellular/eSIM complaints.

If you are affected

AppleInsider advises documenting the problem with both Apple and AT&T support. Some users have tried restarts, Airplane Mode toggles, or line resets with mixed results; one Support Community report described a device swap after the unit was believed faulty. Affected buyers still inside a return window may want to weigh options carefully while a software or carrier fix is unconfirmed.

:::poll{id="92bf8b82-d29e-4593-9538-822f385d9fcf"} If you use AT&T with a new iPhone 18 Pro/Pro Max, what’s your next move on these connectivity reports?

• I’m affected — waiting for a carrier/iOS fix
• I’m affected — considering return/swap or switching carriers
• Not affected, but watching for an official update
• Not on AT&T / not relevant to me :::

Bottom line: reports so far describe a limited subset of U.S. AT&T customers on iPhone 18 Pro Max (and some Pro). Root cause is unconfirmed — treat modem speculation as context, not established fact.