SIM808 not recognising the simcard

Hey guys!
Hope all are doing good.
I was doing a project for which I need sim808 module.
While checking SIM808 module, I connected power supply to the module and attached sim and GSM antenna.
But, SIM808 didnt connect to the network, What could be the possible reason.

I am attaching the picture of the sim I used and the SIM808 sim holder and the Sim card.

Sorry,I wasnt able to add the sim card image…
I am attaching here!