Approving this iPhones
I am trying to approve my iPhone 7 and I am on my trusted device (iPhone 5c) but no messages about approving the iPhone 7 have come up and when I go on here on my Apple ID account it says the 7 is trusted but it won't let me use the Apple ID and keep saying saying approve this iPhone on the 7 but how do I do that
iPhone 7, iOS 12