Talked to MBTrading. They are fine on their side.
Then, I troubleshoot the problem, it looks like it is the ISP issue (SBC Yahoo DSL problem).
$ traceroute www.mbtrading.com
traceroute to mbtrading.com (216.52.236.30), 30 hops max, 38 byte packets
1 home (192.168.1.254) 6.981 ms 1.017...