We have hundreds of these units, and periodically some units wont stay connected on the Cellular RF link from the device to the cellular network.
The unit show IMSI attached in the cellular network core, but there are no signs of life on the Radio link.
As a result the unit becomes unreachable, for long periods of time.
Any suggestions will help.
It sounds like you should work with your re-seller and your carrier to help determine what’s wrong. You’ll probably want to perform a firmware update and ensure the unit is running the latest release, which is 4.4.2. You can try clearing the Non Volatile settings out of the modem, and programming the APN and settings back into the device. You may want to test with another SIM card as well, and see if the issue follows the SIM card or the modem. Your reseller should be able to help you capture the log files and interpret them for your device.