My brand new iPhone 7 Plus won't let the sim work, my new sim is activated and works in my old iPhone 6 but will not work in my new iPhone?

My brand new iPhone 7 Plus won't let the sim work, my new sim is activated and works in my old iPhone 6 but will not work in my new iPhone?

Try removing sim card put back in then reset network settings or can try removing sim card and cleaning the gold pins on it with alcohol n put bk in