mx-esva-01.serverlet.com has no NS records.
NS records for this zone are defined at serverlet.com.
NS records for this zone are defined at serverlet.com.
Question and response
Question
dig mx-esva-01.serverlet.com. NS
Answer
The response has no answer records.
Authority
serverlet.com. 3600 SOA ns1.serverlet.com. info.serverlet.com. 2026022291 10000 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0