DNS error


#1

Hello, When i pull up a DNS lookup
one of my domains returned this,

ERROR: One or more of the nameservers listed at the parent servers are
not listed as NS records at your nameservers. The problem NS records are:
ns2.dreamhost.com.
ns1.dreamhost.com.”

What is this mean? the domain is iet.edu.lk
LK is the sri lanka’s prefix
pls someone help me!!!