How to Fix iPhone 17 Cellular Data Not Working After iOS 26.3 Update
iPhone 17 Cellular data not working after ios 26.3 update usually means the update changed a key setting, left broken temporary data behind, or caused the affected app or service to stop loading correctly.
Follow the fixes below in order. Test the exact problem after each step so you can stop when the issue is resolved.
For more help, also visit the iPhone 17 hub.
Fix #1: Toggle Airplane Mode and restart the iPhone
A quick radio reset often restores mobile data after an update.
- Turn Airplane Mode on for 30 seconds.
- Turn it off again.
- Restart the iPhone 17 and test data.
Fix #2: Check the active cellular line and carrier settings
Data may fail if the wrong line is selected or the carrier bundle needs updating.
- Open Settings > Cellular and confirm the correct line is enabled for data.
- Go to Settings > General > About and install any carrier settings update if prompted.
- Test LTE or 5G again.
Fix #3: Reset network settings
This is the strongest non-destructive fix for persistent mobile data problems.
- Go to Settings > General > Transfer or Reset iPhone > Reset.
- Tap Reset Network Settings.
- Reconnect and test mobile data again.
Fix #4: Check eSIM status and carrier provisioning
A broken or partially provisioned eSIM can stop mobile data completely.
- Open Settings > Cellular and check whether the line looks normal.
- Toggle the line off and back on.
- Contact the carrier if the line still fails to register.
Fix #5: Install a newer iOS patch or contact the carrier
Some modem issues need a follow-up patch or carrier-side refresh.
- Install any pending iOS update.
- Test data in another area if possible.
- Ask the carrier to refresh provisioning if the problem continues.