iphone 5c switching off if i keep my sim?

my iphone 5c is factory unlocked so, first i used to use some sim(1) in it after that i have updated and kept my another sim(2) then with in 5 min it's switched off again started and using again switched off with in 5 min why? so, i have tried restored ios and again kept my sim(2) again it's getting same problem, again i restored and did not kept the sim(2) now it's working good ?plz help me.