Hi,
It indicates that either the module is not detecting the SIM or having an incorrect PIN or the signal strength is less than -111 dBm. However, you confirm that internet access is fine from the device and it's the LED's only that do not display the signal strength ? Also, from the GUI, Please check and share the values seen for the "mobile" factor : Signal strength (RSSI), SINR, RSRP, RSRQ, EC/IO, RSCP, Bytes sent/received, connected band. If the other SIM slot is unused try inserting the SIM to that slot and check if same behavior is seen. Lastly, backup the running configuration on the RUT and do a factory reset, install the config and then check by inserting the SIM to observe any changes in behavior.
Thanks