There are several threads on this bug, most are marked "Solved" THE ISSUE HAS NOT BEEN SOLVED. Using NIS 2012 [19.5.1.2], all updates. Using Win 7 64bit.
When I ran a reputation scan I get an error few seconds in: "Connection Warning, Trust Level, Prevalence, Resource Usage and stability reported for files may not be accurate because norton insight cannot connect to the Symantec server.
On 10 Sept 2011 Michaell, Symantec Employee, wrote: "There are a lot of people at Symantec aware of the problem and we are all interested in getting this resolved asap." Based on this statement, one assume that Symantecs programmers could have fixed the issue in almost 5 months. Obviously, Symantec needs more or better programmers.
Incidentally, in my case, all my internet connections are good, even when called by NIS. It works on another computer on the same router and the same OS, Win 7 64bit.