ERROR: One or more of your nameservers did not respond:
The ones that did not respond are:
One or more of your nameservers did not return any of your NS records.
You may check your nameserver / domain via

When you received similar messages to ones above, it may indicate you need to setup your VPS to accept connections (setup your vps nameservers).

First step is registering new nameservers in your domain registar (godaddy, namecheap and similar). yourvpsip yourvpsip

I registered nameservers manually and now they point to my VPS... but i still get above messages, so i need to setup VPS nameservers on vps side.

Here is more about that:

There are links on how to do it on Kloxo. If it dont helps, please use google to search like: yourvpscontrolpanelnamehere setup domain tutorial