The notification says that it isn't receiving hits and it may have been tagged incorrectly?
For reference this site is at least four years old and it stopped registering traffic about a week ago. I only realized it when I went to review my referral traffic after this holiday weekend. I know there was traffic because people were on the website while in my shop so I don't know what happened. The site is still live and I did not change any Google settings - I rarely touch Analytics settings, only review them.