cleanserver1.mxserver.ro has no NS records.
NS records for this zone are defined at mxserver.ro.
NS records for this zone are defined at mxserver.ro.
Question and response
Question
dig cleanserver1.mxserver.ro. NS
Answer
The response has no answer records.
Authority
mxserver.ro. 1800 SOA norman.ns.cloudflare.com. dns.cloudflare.com. 2396940820 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0