Seems like joker.com is having issues with their DNS again:
Joker.com currently experiences massive distributed denial of service attacks against nameservers.
This affects DNS resolution of Joker.com itself, and also domains which make use of Joker.com nameservers.
We are very sorry for this issue, but we are working hard for a permanent solution.
Thank you for your understanding,Your Team of Joker.com
Ah, that explains yesterday.