I am trying to use the nano sim from my Samsung Galaxy S6 4G LTE phone (it is in full working condition) in an unlocked iPhone 5S. As the sim card was already active, I put the sim in there and turned on iphone 5S. I get internet (without WiFi) but I cannot make any calls. It shows LTE on the top left but all the bars are grayed out. I cannot make any calls on WiFi either.