Apparently my daughters phone can't activate?

She turned her phone all the way off, in effort to help with it being slow. She turned it back on and it said "update complete" even though she didn't update it. It asked her to choose a wifi network, and she chose ours, and it loaded for a second then said it couldn't be activated. She tried again using cellular instead of wifi, and the same problem occurred. She's repeated the process many times, and it still says her phone can't be activated