On my second Moto G and second SIM card, third phone is in transit to me now. About a month after receiving the phone began getting error message that there was no SIM card. With guidance from Motorola support have performed factory reset (and lost all my phone numbers despite first backing up to google account and cleared the cache. Only thing that works is removing the back of the phone, taking out the SIM card and reinserting. Fix can last an hour or a week. New phone and new SIM card made no difference.