Hi and thanks for answering me. I have been experiencing the problem for about 20 days on 3 modems installed in different locations. today, I connected the modem to the pc to see what was really happening. i had different problems. the problem common to all three is that the modem was really stuck , so much so that to log into the webui I had to force a restart by disconnecting the power supply. once the first modem was started, the mobile connection was restarted, while the "sim not inserted" error was present on the other 2 modems (even if it was correctly inserted) and even doing more than one reboot, it did not connect to the internet. To solve, I had to extract the sim and reinsert it. I can confirm that the modem case is very hot, and the internal temperature sensor shows 65/70 degrees
thanks again for the help