AT&T has acknowledged that some iPhone 18 Pro Max devices are experiencing persistent or intermittent cellular connectivity failures, often forcing phones into SOS mode. While the carrier is urging users to install iOS 27.0.1, many customers report that the update fails to resolve the issue, leaving some without access to 911 services.
iPhone 18 Pro Max Users Report Widespread Connectivity Failures
Owners of the iPhone 18 Pro Max have reported significant disruptions to their mobile service, with many devices losing the ability to place calls, send text messages, or access data. The problem frequently triggers the phone to enter SOS mode,
rendering the device unable to connect to the AT&T network. Reports indicate that these connectivity issues occur both persistently and intermittently for users across the United States.
The scale of the problem appears widespread, with thousands of user reports documented across the Apple Support Community, Reddit, and various enthusiast forums. While no official count of affected devices exists, the severity has prompted concerns regarding basic emergency functions. In a text message sent to customers, AT&T explicitly warned that the connectivity problems may be unable to complete calls/text/data, including to 911.
The iOS 27.0.1 Update Controversy
In response to the outages, AT&T has directed customers to install the latest software update immediately. The carrier’s message instructs users to navigate to Settings > General > Software Update
to download iOS 27.0.1. However, the effectiveness of this recommendation is being challenged by the very users experiencing the outages.
Many customers have reported that the update does not restore network access. This lack of resolution is further complicated by Apple’s official release notes for iOS 27.0.1, which make no mention of a fix for cellular connectivity problems. Instead, Apple stated that the update resolved a Face ID issue on the iPhone 18 Pro models.
Qualcomm Modem May Contribute to US Service Failures
The U.S. version of the device is the only model in the new lineup to feature a Qualcomm cellular modem; the smaller iPhone 18 Pro and the iPhone Duo utilize Apple’s proprietary C2 modem worldwide. While the iPhone 18 Pro Max uses the C2 modem in all other international markets, it remains unclear if the Qualcomm modem is a contributing factor to the current service failures.
Apple has not yet provided a public comment or confirmed the underlying cause of the issue. If the root cause is identified as a software bug, industry analysts suggest a subsequent update, such as iOS 27.0.2, may be required. Conversely, should the investigation reveal a hardware fault, the resolution path would be significantly more complex. For now, users remain without a confirmed solution, and some have expressed frustration with the lack of clarity from both the carrier and the manufacturer.
An affected iPhone 18 Pro Max user reported experiencing issues with their AT&T service, including the phone entering SOS mode, which prevented calls despite WiFi functionality. The user mentioned they had tried various solutions and contacted AT&T, but the problem remained unresolved, according to MacRumors.
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