Hi Fred
Thank you for the follow-up information.
The IP Address assigned to the modem [10.12.245.242] is a private IP, firewalled by the cellular carrier.
You won’t be able to access the device remotely unless you work with your cellular carrier (SIM Provider) to get “Mobile Terminated Data Service”.
The only other option with the SIM service you currently have would be to use DeviceHQ.
DeviceHQ is a Cloud based management platform you can use that is included with the purchase price of the device.
https://www.multitech.com/brands/devicehq
-Best Regards