SIM cards troubleshooting
Diagnose SIM card issues like searching or unregistered status, USSD errors, missed SMS, or unreachable robots with this troubleshooting guide.
A SIM that misbehaves shows up either through its status (searching, unregistered) or through recurring errors in test results. Here is the diagnosis for each case.
- Reboot the slot, or the robot.
- If the status stays searching after 10 minutes, insert the SIM in a phone and check whether it connects to the network.
- If it connects in a phone, the modem's IMEI has likely been banned by the operator: investigate that side.
- If it does not connect in a phone either, the SIM itself has a problem or the network coverage is very poor.
The SIM has probably been deactivated by the operator because it always stayed connected to the same antenna. Reboot the modem; if it stays unregistered, test the SIM in a phone and replace it if it does not connect.
The cellular network did not answer a USSD session opening request. Possible causes: bad network coverage, an outdated USSD licence, or an overloaded USSD server.
To confirm the request left the modem, open the pcap artifacts (radioframes) attached to the test result and look for:
UplinkDirectTransfer ... invoke processUnstructuredSS-Request: the request was sent.DownlinkDirectTransfer ... invoke unstructuredSS-Request: the network replied.
If the request is sent but never answered, contact your USSD provider.
Reboot the modem, then contact support if it persists.
The SIM refuses USSD actions. Reboot; if that does not help, escalate to the operator's network team.
Check the SIM's history in the platform: the SMS may simply have arrived after the timeout.
Either the SIM has no airtime, or it is not allowed to call this number (short numbers, or unavailable while roaming).
Either the robot is not connected (a robot that stays Offline), or, if the agent shows available in administration, the robot's clock is out of sync: ask support to check.
What's next?
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