My SIM stopped working - what can be the problem?

These are common issues that can cause a SIM to stop working: 

PREPAID SIMs

Check the SIM balance and recharge rule

Check that the SIM's recharge rule is set up correctly, and that the SIM has enough data/airtime available. Remember that the balance shown on SIMcontrol could be a few hours old. You can update the current balance under "SIM Actions / Balance Check SIM". Another  simple test is to load the SIM with a small airtime amount, to see if it comes online. 

Check that your account has funds available

If your account has run out of funds, recharges can not be processed. Check that your account is sufficiently funded to allow recharges to trigger. 

Are you using the correct APN?

Check your device's APN settings. The APN should be set up according to the network you are using. See a library of network settings here. 

Is the device powered up?

Could your device be switched off or run out of power?

If the device is battery-powered, is there enough charge?

Low charge on some devices can affect connectivity. Please ensure the device is fully charged or attached to a charger while troubleshooting.

Does the problem persist if you power-cycle (reboot) the device?

Turn off the device and then turn it back on. If the device is battery-powered, remove the battery for 60 seconds and then re-insert the battery. The 60 second delay eliminates all power in the device and ensures a clean reboot for the device application and radio modem hardware. If a remote device, trigger a remote device restart via SMS. 

Does the device have coverage?
Check your operator's coverage maps to make sure the device has coverage in its current location. Also, networks do experience down-times in specific areas from time to time. If you try and call a SIM and it rings, it typically means the device is within range. Networks do not disclose specific tower or area outages, but a good guide for larger network issues or outage is Downdetector - https://downdetector.co.za/ 

Are there other functioning devices in the same tower/area?
If so, network coverage is likely to be fine. 

Is the signal strength powerful enough?
If the device has a signal strength meter, check the reading. If not, try checking the signal strength of the installation using a cell phone on same network in that area.

Can you make an SMS connection?
Send an SMS to the device. If this works, the device can make a GSM connection to the network.

Network upgrades
Mobile networks occasionally roll out tower and system upgrades. This may force SIMs to disconnect from the network. Especially older GSM devides using CSD data (Circuit Switched Data) would then not automatically re-attach to the network. In these case devices would need a reboot or you need to trigger a outbound SMS to get them online again.

Does the SIM work in another device?
If possible, remove the SIM and insert it in another device or an unlocked mobile phone. Make sure to set the APN correctly in the new device before testing the connectivity. If the SIM works in another device, then you can assume the original device is faulty or has incorrect settings. 

Is the SIM is properly installed and seated correctly?
Sometimes a SIM is inserted incorrectly at the factory or knocked out of place when the device is opened for servicing or battery replacement.

Does another SIM work in the device?
Try replacing the SIM with another. If the new SIM works, then there is an issue with the original SIM. SIMs only have a limited cycle life. High temperatures can also cause damage to SIMs or cause warping of the SIM affecting the contacts. 

MANAGED APN SIMs

Addition trouble-shooting:

• Does your account have an active Pooled Data bundle?
• Does the SIM have Quota available, and is the SIM linked to a Quota rule?
• Is the device set up with the correct Managed APN name? 

GLOBAL ROAMING SIMs

- Check current configuration on the platform, and make sure credit is available on the SIM

- Check if the correct APN name is configured on the device

- Check if data roaming is allowed on the device

- Restart the device

- First connectivity of the SIM could take a longer time than normal, so if it is first connectivity attempt, leave the device on for some time.