Yeap, thanks to golden frog support. It was actually easy (after you know it!). I had NOT to use the ISP DNS servers and fill-in in the router another set of DNS IPs (e.g. OpenDNS). All works now!
"To setup the DNS servers in your router firmware, click the WAN tab on the left. Under WAN DNS Settings, set "Connect to DNS Server automatically" to No and enter a pair of the DNS servers' IP addresses. After setting the DNS servers, click the Apply button at the bottom and then Reboot your router."
Hope this helps others with the same problem.