Yes, the problem is with the ISP (ACT).
The URL you're trying to reach has been blocked!

Yes, the problem is with the ISP (ACT).
If you use Windows, maybe you could try to change the DNS server with this nifty freeware utility:
https://www.grc.com/dns/benchmark.htm

You need to contact your ISP and try to figure out why they've blocked the URL.
You could also try V3, as those URLs are configured differently, and see if those are blocked. I think you can try V3 by joining the http://www.chess.com/groups/view/chesscom-v3 group
It is not opening for me too. Getting same error .I am using ACT