A phone or tablet problem starting right after an OS update, a new case/accessory or a restored backup should be checked against that change first. For iPhone cellular data, first test a call and public website in two locations with Wi-Fi off and VPN disabled.
What this covers
- iPhone cellular data with this exact failure state
- Diagnosis across carrier outage/account versus SIM/eSIM, coverage, VPN and per-app data settings
What it does not cover
Try in this order
0 of 4 completedCapture the exact failure state
ReversibleNote the exact update version, accessory or backup date, and confirm the feature worked immediately before it. Expected behavior: attach to the carrier network and route allowed app traffic at the provisioned service level.
Isolate the component boundary
ReversibleTest a call and public website in two locations with Wi-Fi off and VPN disabled. Test with the new accessory removed, or check the update's known-issues note for the exact symptom. Boundary to separate: carrier outage/account versus SIM/eSIM, coverage, VPN and per-app data settings.
Correct only the proven cause
ReversibleInstall carrier settings, correct the selected line/data permission or contact the carrier. Reset the one setting the update changed, or replace the incompatible accessory.
Verify and stop safely
ReversibleConfirm normal operation with the change present for one full day of typical use. Seek carrier or emergency support when service loss affects urgent calling.
Evidence ledger
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