Apple ID

I've just got the new iPhone 12, it's all set Up, I paired it with my old phone so the new phone did all the hard work for me. But some reason, on settings, it keeps asking to sign into apple ID, even though I'm already signed in. It keeps asking for my password. I put it in, press Continue and then the screen just Freezes!! It's Constantly got a notification for it and it's annoying me now.. Can anyone help...