Hello,
To begin with, please make sure that both LTE antennas are connected to the router.
Then navigate to "Status -> Network -> Mobile" menu and check if router can detect SIM card ("Sim card state" field) or if SIM PIN code needs to be entered.
If router indicates that "Sim card state is Ready", please navigate to "System -> Administration -> Troubleshoot" menu, download troubleshoot package from the router and send it to me via private message.
Also, could you let me know if you have tested this SIM card in any other device? If no, could you try doing so (e.g. try to use it in mobile phone) to check if it is working?