smtp2.apcob.org has no CNAME records.
Question and response
Question
dig smtp2.apcob.org. NS
Answer
The response has no answer records.
Authority
apcob.org. 600 SOA ns63.domaincontrol.com. dns.jomax.net. 2025120401 28800 7200 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0