Can't access one specific subdomain

Using OSX 10.10.2 on a MBA 11" I can't access

http://ift.tt/1rpfhKD

I flushed the DNS, rebooted my machine, connected via iPhone instead of WLAN (I can access the site via iPhone directly, but not when using the iPhones Network-connection on the Mac.

Tested on all installed browsers.

So, I'm out of ideas and look forward to yours.