SIM not connecting
SIM not connecting? Check power, signal, SIM seating and that the device is set to use mobile data. Restart once; repeated restarts can hide the real fault.
First work out which kind of “not connecting” it is
| What you see | What it usually means | Go to |
|---|---|---|
| No signal, “no service” or “SOS only” | The device is not registering on any network | Section 1 |
| A network name shows but there is no internet or data | Registered, but the data session is not starting | Section 2 |
| It connects, then drops or comes and goes | Marginal signal, power dips or an unstable network mode | Section 3 |
1. The device does not register on a network
- Power. Use a stable supply. A device that browns out on start-up or when a motor runs may never finish registering.
- SIM seating. Power down, check the SIM is the right size and orientation and fully seated, and do not force the tray. See replacing the SIM.
- Antenna. Confirm it is connected, undamaged and clear of metal. See weak or no network.
- SIM PIN. If the SIM asks for a PIN and the device cannot supply one, it cannot register.
- Activation. Confirm the SIM has been activated for this device.
- Network and radio settings. Leave network selection on automatic unless you have been told otherwise. A device locked to 3G-only or one network can have nothing left to connect to: see the 2G and 3G switch-off guide.
2. Registered, but no data
- Mobile data is switched on in the device settings.
- APN. Many managed devices set their APN automatically. If yours needs it entered by hand, see APN setup. A wrong or missing APN is the classic cause of “registered but no internet”.
- Roaming. If the device reports roaming, check whether data roaming needs enabling.
- Plan. Check the plan includes data and that the allowance is not used up.
3. Connects, then drops
- Signal. Record the signal reading over a day rather than once. A marginal signal that dips at busy times looks like a random fault.
- Power. Look for dips under load, such as a motor, heater or relay starting.
- Network mode. A device that hops between 2G, 3G and 4G can drop the session each time. Do not lock the mode unless your supplier advises it.
Restart once, not repeatedly
Restart once after checking the installation, then note the result and change something else. Repeated restarts hide the real fault. Change one thing at a time and avoid unverified programming codes, resets or account changes.
What to send us
- The ICCID printed on the SIM and the device model
- Exactly what the device shows: no service, a network name, or a data status
- Signal readings, or a photo of the status page, with the time they were taken
- When it last worked and what changed since
Frequently asked questions
Why does my device show a network but no internet?
That normally means it registered on the network but the data session did not start. Check that mobile data is switched on, that the APN is right if your device needs one set by hand, the roaming setting, and that the plan includes data with allowance remaining.
How long should I wait after inserting the SIM?
Give the device a few minutes to register. If nothing has changed after that, restart it once and note what happens rather than restarting repeatedly.
Can I test the SIM in another device?
Yes, with both devices powered down first. If the SIM works elsewhere, the fault is in the original device or its settings. If the SIM is assigned to a specific device or customer record, ask Engineer Support before moving it permanently.
Still stuck? Engineer Support can continue from this guide without sending you to a generic page.