Not really that unusual. I see this sort of thing all the time at work.
For example, one person had a firewall set to block keywords. He did not realize that those keywords he put in would block anything with that string
of letters in it. For instance, if you put the keyword "bel" in some firewalls, it may block BELowtopsecret.com.
There are just so many settings to check that sometimes the best thing to do is start at the very basic level.
Perhaps you could try to ping the site.
Start
run
type: cmd
type: www.belowtopsecret.com
Press enter
Did you get
A reply
destination unreachable
request timed out
You should also ping the site IP address, and note the response.
Then you can do a: tracert www.belowtopsecret.com
This will show the replies from each router on the way to the site. If it fails, where was the last response from. That is where the problem is.
The type of replies will give you a basic troubleshooting starting point.
Also, be aware, Just because the major network routers picked up on the DNS replication, not every ISP updates their DNS cache on a timely basis. If
the tracert fails at your ISP, maybe you could ask them about it.
Best of Luck
makeitso