pr0.mxout.mta2.net has no CNAME records.
Question and response
Question
dig pr0.mxout.mta2.net. NS
Answer
The response has no answer records.
Authority
mta2.net. 600 SOA pdns09.domaincontrol.com. dns.jomax.net. 2024031400 28800 7200 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0