smtp2.svitonline.com has no CNAME records.
Question and response
Question
dig smtp2.svitonline.com. NS
Answer
The response has no answer records.
Authority
svitonline.com. 736 SOA ns.sovamua.com. domaintech.kiev.sovam.com. 2020011800 14400 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0