Passport- SIM don't works - any idea?

Hi, i turned on my Passport again after some times,
everything works excpets the SIM registration on carrier network.
The SIM is recognized, it's active, the same SIM works on Z10, the carrier network name appears in the quick setting panel Network, but..
the phone line is not working, it's not registered, symbol red (!) near che phone icon..
I already reflashed firmware,
has anyone had the same problem?
any idea?
thanks,
any suggestions will be highly appreciated
Cristian

My idea is the dreaded no Service issue that Passports seem to develop when antenna connections... break.

If your up of opening it up and doing so soldering there is a resolution.

Thanks a lot, it make sense.
Actually, the network is found, so I was not thinking about an antenna problem