I have NIS 2005, and have no problems updating with Live Update. However, the programme does seem to slow things up.
You could try updating manually from this site:
New Norton AV definitions are released daily.
Samsung Galaxy S8 review
1995-2015: How technology has changed the world in 20 years
What’s happening in VR right now: From psychedelic art to combat therapy
Siri not working? Try these troubleshooting fixes
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.