Latitude 5280 problem with sim card

Hello! Such a problem.. Dell Latitude E5280. Cellular network suddenly dropped. There was no wwan modem from the factory, there were antennas. I bought a modem Sierra Em7455, installed the driver, everything started, connected to the cellular network, everything is fine!!! And one day win 10 writes -  insert a sim card... I reinstalled the driver, updated win10, etc. It does not help .. There is an idea that the matter is in the antennas. On the wifi module, as a test, I turned off the antennas and win10 writes - no networks were found. It may be the same here that the wwan modem does not receive a signal and the system thinks that there is no SIM card ... But the antenna wires go deep under the motherboard, where can there be a receiver?  And how could she be hurt then? What are the wires from the modem connected to? The SIM card slot is located on the motherboard itself and is not directly connected to the modem.
Do you have any thoughts what could be? Well, Windows couldn't just break down and stop connecting from the cellular network? In this case, only reinstalling win10 will help? Previously, everything worked. The laptop is not cluttered, not flooded, etc. The sim card is working, tested on the phone. Also used other sim cards.. Help please...