Thank you, I did it.
However, I can't see how can it be possible that poloniex.com works and www.poloniex.com doesn't.
polonex.com and poloniex.com are two different things, if you are logged in poloniex.com you are not logged in on www.poloniex.com, basically the verification emails that are from poloniex are with "www" before.
But this has nothing to do with DNS, as far as I know.
Not related to his DNS issue, they have been under heavy DDoS attacks the last few days. It has been resolved now, as it seems.