How to use free DNS?

Question

Domain Name System

I ordered a VPS with one ip on isp manager. And I decided to take a free DNS.
the registrar indicated:
ns1.mydomain.com
NS2.AFRAID.ORG
and the ip of my VPS
on AFRAID.ORG added my site
and on the VPS, respectively:
ns1.mydomain.com
NS2.AFRAID.ORG
At first, the content displayed on the site was what was needed . And then a page with AFRAID.ORG. Now again knocks out a normal page. What's going on that I'm doing wrong?

Answer 1

https://www.cloudflare.com/ best for DNS and more

Answer 2

Write to the host, most likely their dns is down