mx.wowway.com has no NS records.
NS records for this zone are defined at wowway.com.
NS records for this zone are defined at wowway.com.
Question and response
Question
dig mx.wowway.com. NS
Answer
The response has no answer records.
Authority
wowway.com. 1800 SOA elinore.ns.cloudflare.com. dns.cloudflare.com. 2397021372 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0