A SIM-related message is a clue, not a complete diagnosis. Wording varies between iPhone, Android manufacturers and networks, but most messages fit into four groups: detection, registration, provisioning or security.
Quick interpretation
| Message | What it usually means | First action |
|---|---|---|
| No SIM / SIM not detected | The phone cannot read a physical card or cannot see the selected line | Restart, inspect the tray and check SIM settings |
| Invalid SIM | The card may be unsupported, damaged, inactive or restricted | Check account status and whether the phone is unlocked |
| SIM not provisioned | The network has not activated or associated the SIM correctly | Contact the provider with the exact message |
| No Service / Searching | The readable line is not registering | Check coverage, outage, account and network selection |
| Emergency Calls Only | Normal service is unavailable; the label does not prove an emergency call will complete | Do not test 999/112; troubleshoot ordinary service |
| SIM PIN / Enter PUK | The SIM security code is required or has been entered incorrectly too many times | Stop guessing and obtain the code from the provider |
| Network locked / SIM not supported | The handset may be restricted to another provider or the device-plan combination is unsupported | Check unlock status and provider compatibility |
No SIM and Invalid SIM
Confirm that the plan is active, the card is seated correctly and the phone is unlocked for the intended network. Try the provider's replacement process if the card is damaged. Imported or older devices deserve an additional compatibility check.
SIM not provisioned
This normally requires provider action. It may appear with a new SIM, replacement SIM, number transfer, account suspension or incorrect activation. Restarting repeatedly cannot complete missing account provisioning.
PIN and PUK warnings
A SIM PIN protects the card, while a phone passcode unlocks the handset. After repeated incorrect SIM-PIN attempts, the card may require a PUK. Do not guess: too many wrong PUK attempts can permanently block the SIM.
Emergency Calls Only
This message means the phone does not currently have normal service on the selected line. The ability to reach emergency services depends on available networks, device support and location. Never make a test call to 999 or 112.
When the message follows a SIM swap or port
Allow for the provider's stated activation window, then ask it to confirm which SIM serial or eSIM profile is attached to the number. Keep both old and new devices available until the switch is complete.
The point to verify before relying on it
Copy the message exactly before taking action. 'No SIM', 'SIM not provisioned', 'PUK required', 'network locked' and 'Emergency Calls Only' describe different layers of the service. Matching the wording to the correct layer prevents destructive resets and gives the network or repairer useful evidence.
- Do not guess a SIM PIN or PUK repeatedly.
- Check account activation separately from card detection.
- Never test an emergency-only state by calling 999 or 112.
Official information checked
Information checked on 25 July 2026. Exact wording and recovery steps depend on the device and network.
