I have an iPhone 6. When I put my SIM card it perfectly works but not in 5s?

I tried putting my dad SIM card in I6 n 5s.Sim worked well. But when I put my sim in 5s it shows no sim but works fine in I6. Give a suggestion

Read more: I have an iPhone 6. When I put my SIM card it perfectly works but not in 5s?