This can usually be a problem when the SIM card is not read or is in it. In case you use a different card and it works the problem is in the cards, otherwise it can be more difficult to solve it, in case the problem is in socket. One of my friend had a problem like this, as i understood from he tried to do some modification with the sim cards, to change the codes there. As I remember he used https://www.sccatl.org/ and 2 more programs, but it was not possible to do anything, the socket came with some problems.