Check that you have inserted the SIM card correctly. You can find information about this in your phone's user guide. If the card or the contacts are not clean, clean them both with a dry non-fluffy anti-static cloth. If the card still does not work, it may be faulty. Please call the appropriate customer service team from another phone.
Tip: If this article didn't answer your question, please see if a similar question has already been answered in the Support Forum. If not, please post your question; other customers may be able to help.