mx4.svitonline.com has no CNAME records.
Question and response
Question
dig mx4.svitonline.com. NS
Answer
The response has no answer records.
Authority
svitonline.com. 1016 SOA ns.sovamua.com. domaintech.kiev.sovam.com. 2020011800 14400 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0