mx.ovh.com has no NS records.
NS records for this zone are defined at ovh.com.
NS records for this zone are defined at ovh.com.
Question and response
Question
dig mx.ovh.com. NS
Answer
The response has no answer records.
Authority
ovh.com. 600 SOA dns.ovh.net. tech.ovh.net. 2026022099 86400 3600 3600000 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0