As stated, we've been trying to figure out this issue for a very long time but unfortunately we have been unable to reproduce the issue. It definitely has something to do with the user's internet connection and the user's PC but the exact nature of it is difficult to determine as everybody's set up is different.
We'll continue to investigate this matter and see if we can come up with a solution. However, at this time, all known attempts to fix this issue (ip reset, dns flush, power cycle, etc.) have little to no success. We apologize for the inconvenience and we'll do our best to continue figuring this out.