A SIM that switched itself off was almost always switched off by something you configured, or by your account balance. Simbase does not disable SIMs at random. Work out which of the six causes below applies, because the fix and the risk of it happening again are different for each.

Find out what disabled it

Open the SIM in the dashboard and run Diagnostics. It reports the SIM's provisioning state, including caps and theft protection, and will usually name the reason directly. See Diagnostics.

One quick signal before you look at anything else: is it just this SIM, or all of them? If every SIM on the account is disabled, it is the balance. If it is one SIM, it is a rule attached to that SIM.

What disables a SIM

Zero balance disables everything

This is the one that surprises people, because it is not a per-SIM setting. When the account balance reaches zero, every SIM is disabled, including ones that have barely used anything.

Topping up restores service within minutes. To stop it recurring, set up auto-recharge, and make sure the low-balance alert goes to an address someone actually reads. See Account balance and invoices.

Usage limits and Auto-Disable

Both switch a SIM off deliberately, which is what they are for. The question is whether the threshold was set too low, or whether the device genuinely used more than expected.

Check the SIM's usage against the limit before raising it. A device that hit a sensible cap early is telling you something about its behavior, and raising the cap without looking just moves the problem to a bigger bill. See Usage limits and Auto-Disable (for Green Profile SIMs).

Theft protection

If theft protection is enabled and the SIM is placed in a different device, the IMEI mismatch disables it automatically. This is working as designed, and it catches legitimate hardware swaps as often as it catches theft.

Either put the SIM back in its original device, or manually enable the SIM to pair it to the new IMEI. See Theft protection.

Re-enabling the SIM

Fix the cause first. Re-enabling a SIM without clearing what disabled it usually means it disables again, sometimes within minutes.

1. Resolve the cause, top up or adjust the limit

2. Set the SIM's state back to Enabled. See SIM state

3. Reboot the device, or use Reset connection, so it attempts a new session

The SIM is enabled but the device still won't connect

If the SIM was left in a powered device while disabled, its repeated registration attempts were rejected each time. Depending on the reject cause and the modem, those rejections can add networks to the FPLMN list, the list of forbidden networks stored on the SIM. The modem reads that list when selecting a network and skips anything on it, so it stops trying the very networks it needs.

The list holds up to four networks and may survive a power cycle, so turning the device off and on again might not clear it.

How to clear the FPLMN list

Five options, easiest first. Which are available depends on the device and whether you can physically reach it.

1. Force manual network selection on the device. If the device supports it, turn off automatic network selection and pick an operator by hand. The network you need may be listed as forbidden, which is only the FPLMN entry left by the earlier rejection. Select it anyway. Registering manually clears the list, and the SIM never has to leave the device

2. Put the SIM in a phone. This clears the list in most cases. If the phone still cannot register, switch it to manual network selection and try the available operators one at a time, which also clears the list

3. Remove and reinsert the SIM. Most devices clear the list when the SIM is removed. Power the device down, take the SIM out, power it back on, then reinsert the SIM and reboot again. Needs physical access and a standard SIM format

4. Move the device. Because the list holds only four entries, registration attempts in a new location overwrite the old ones. Rarely practical, since it usually means crossing a border

5. Clear it with AT commands. If you can reach the device's CLI, over SSH on the local network or a serial connection

To read the current list:

AT+CRSM=176,28539,0,0,12

To clear it:

AT+QFPLMNCFG="Delete","all"

Run the read command again afterwards. A response of FFFFFFFFFFFFFFFFFFFFFFFF means the list is empty. These commands work on most modems, but some vendors use different ones, so check your module's documentation if they are rejected.

For a fuller explanation, see What is an FPLMN list.

To avoid this next time, power the device down or remove the SIM before disabling it.

Still disabled

Contact support with:

• The SIM's ICCID

• Whether one SIM or several are affected

• When you noticed it, and whether anything changed around that time

• What you have already tried

• Whether the SIM re-enables and then disables again

Common questions

Related

• SIM state, enabling and disabling SIMs

• Usage limits, per-SIM data and SMS caps

• Auto-Disable, automatic disabling rules for Green profile SIMs

• Theft protection, IMEI locking

• Account balance and invoices, keeping the balance positive

• Connectivity issues, if the SIM is enabled but still offline