Q: iPhone unable to identify my SIM card.

I have an iPhone 5. For some reason, it is not able to identify my SIM card. It just shows No SIM. I've tried everything. My SIM card works in other phones, and I've also put 2 other different nano SIM cards in my iPhone and they work!

This is very strange since my SIM is working on other phones (haven't tried it in an iPhone, though) and others SIM cards are working on my iPhone. I can't figure out if the problem is in my iPhone or in my SIM card. I used iTunes and I restored the iPhone but now it's not setting up because iPhone needs a SIM card to set up. What to do?