mx01.cisco.ukrpost.ua has no CNAME records.
Question and response
Question
dig mx01.cisco.ukrpost.ua. NS
Answer
The response has no answer records.
Authority
ua. 925 SOA in1.ns.ua. domain-master.cctld.ua. 2026030809 1818 909 3024000 2020
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0