I had the same problem as others have noted.
A 'loop' of a Norton popup reporting a webcam access request, and a separate notice that my virus definitions were out of date. 'Fix now' did not work, with no info as to why, of course
. After a few failed attempts, I noticed that my webcam was plugged in (it usually is not), because with Covid-19 requirement to stay in my house as much as possible, I had been using video chats to 'talk' to people.
So I unplugged it, and was able to do the Norton update successfully, and get rid of the annoying popup, and actually update my antivirus definitions.
Hope my experience helps others ( You may just have to 'disable' your built-in camera, in 'Settings', I don't know ).