mail.eleso.org has no NS records.
NS records for this zone are defined at eleso.org.
NS records for this zone are defined at eleso.org.
Question and response
Question
dig mail.eleso.org. NS
Answer
The response has no answer records.
Authority
eleso.org. 3601 SOA dns1.registrar-servers.com. hostmaster.registrar-servers.com. 1772630482 43200 3600 604800 3601
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0