mxout02.corenic.net has no CNAME records.
Question and response
Question
dig mxout02.corenic.net. NS
Answer
The response has no answer records.
Authority
corenic.net. 900 SOA ns2.knipp.de. dnsmaster.irondns.net. 2023120463 10800 3000 2419200 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0