Troubleshooting after APN setup

If APN setup has not restored connectivity, check the selected settings, your device and your line in order. First compare every value with the settings for your subscription and restart the device.

Check in this order

1. Selected APN and iPhone profiles
2. SIM lock
3. Network usage restrictions
4. Device compatibility and VoLTE
5. Activation and cellular data
6. Coverage, outages and individual apps

First check the values and restart

Open your subscription’s entry in the APN list. Check spaces, punctuation, username and password. A shared APN address does not make another carrier’s credentials interchangeable.

Save and restart. Temporarily disable Wi-Fi to test cellular data separately.

References: LINEMO’s connection troubleshooting, APN setup guide.

1. Is the saved APN selected?

Android/Galaxy: Open the APN list and select the entry you saved. Also check that you are editing the intended SIM when using dual SIM.

iPhone/iPad: Check whether your carrier requires a profile. Inspect old carrier APN profiles under Settings → General → VPN & Device Management or an equivalent menu. Remove an obsolete APN profile following carrier instructions. Do not bulk-delete work/school management profiles or delete your eSIM.

References: LINEMO’s save/select instructions, Apple’s APN guidance.

2. Is the SIM lock cleared if required?

If your device is SIM-locked and your intended network requires unlocking, follow the original seller carrier’s procedure. A device sold unlocked may need no procedure.

On iPhone, inspect the SIM lock field under Settings → General → About. Android methods vary. Changing an APN cannot unlock a device.

Reference: UQ mobile’s SIM lock checks.

3. Is the handset under a network usage restriction?

For a used handset, check its IMEI using the original selling carrier’s official restriction checker. This carrier may differ from your SIM provider.

A handset restriction is separate from SIM locking. Contact the seller or carrier if a restriction appears; APN changes cannot remove it. You do not need to submit your IMEI to Toolkit.

Reference: SoftBank’s restriction information and checker guidance.

4. Check compatibility and VoLTE for voice calls

Check the exact model, selling carrier, OS and SIM type in your provider’s compatibility list. Review data, voice, SMS and tethering results separately. An unlisted device is not automatically unusable, but it is not confirmed by that list.

If data works but calls do not: Check that your plan includes voice, that the device supports your carrier’s VoLTE, and that voice calling is supported in the compatibility results. If a VoLTE control exists, configure it according to carrier instructions; some devices have no visible switch.

“4G compatible” or “SIM unlocked” alone does not establish support for a carrier’s VoLTE or required radio bands. An APN cannot add missing hardware or carrier compatibility.

References: LINEMO compatibility list, LINEMO VoLTE guidance.

5. Check activation and the selected line

• Has SIM/eSIM activation and any porting switch completed?
• Does the device recognize the SIM, and are the line and cellular data enabled?
• Are the intended lines selected for data and calls on dual SIM?
• Is service suspended, or is a data allowance restriction affecting use?

For an unrecognized SIM, follow the carrier’s SIM/eSIM procedure. Deleting or reissuing an eSIM is not the first step.

References: Apple cellular data guidance, Apple SOS/No Service guidance.

6. Separate coverage, outages and app issues

References: Apple reception troubleshooting, Safari connection troubleshooting.

What to tell support

Provide your model number, original seller, OS, plan, SIM/eSIM type, error message, whether data or calls fail, and steps already tried. Do not post APN authentication passwords or IMEI numbers in public comments.