Something changed inside their network when they did whatever they did. The most likely cause of what you experienced is that there are multiple routers handling incoming traffic, and the pathway to get to the download server was "blocked" because the location changed inside the network, either by the fact that the router itself was replaced and that router didn't know what the new location was for the download server, or the download server got replaced. Other people can come into the network on other routers that do know the location of the download server, so they proceeed in without a problem.
There are other possibilities, but in any case it was a problem inside their network that was the cause of the problem, not anything on your system. Generally speaking, when hundreds / thousands of people suddenly start experiencing the exact same problem, the problem is not on each individual's computer. That's not to say that doing the standard "level 1" stuff of deleting cache / cookies shouldn't be done. It, however, is frustrating to me to watch people jump through hoops when it seems that the problem is elsewhere...




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