I've got a number of devices with Norton Security installed - all good except one. The Windows 10 PC shows on the web interface as "Not protected" - but Norton Security is installed and activated. I even tried to reinstall this morning, but it just verified that it was installed. On the PC NS shows "you are protected" and subscription status is Active.
I had something similar on my laptop where even though Norton was installed and working Windows stated Norton was not protecting me for the firewall or viruses. After some research I found C:\Windows\System32\wbem\Repository was corrupted. However this folder is protected by Windows and you cannot delete it. I needed to boot from a Windows install disk and use the command prompt to delete that directory. When I rebooted Windows automatically recreated that directory and Norton was properly recognized.
The notification is the following "No security products found on your device". Which blatantly isn't the case. :)
I've spoken to support in the interim and they said it was a data sync issue and that it was being worked. Apparently seen more often on devices which had been upgraded or restored. The latter might apply to me - but since it is more an annoyance than a big issue - I've got green lights across the board on the application on the PC - then I guess I'll have to live with it in the meantime.