We are currently facing an attack on the OrderBox DNS servers, on account of which the DNS records (A, MX, PTR, etc…) could not be fetched.

Below are the IP addresses which have been null routed due to the attack:

50.23.136.173
50.23.136.174
50.23.75.96
50.23.75.97
50.23.75.44
50.23.75.45
50.23.136.230
50.23.136.229

We are working in co-ordination with the data center to mitigate this attack as soon as possible. Please follow this thread for more information.

Feel free to contact the support team, in case of any further queries or concerns.

SOURCE:

http://forums.myorderbox.com/index.php?/topic/5572-attack-on-dns/
https://support.resellerclub.com/helpdesk/index.php?/rcsales/Core/Default/Index