mail.viczem.org has no CNAME records.
Question and response
Question
dig mail.viczem.org. NS
Answer
The response has no answer records.
Authority
viczem.org. 1800 SOA burt.ns.cloudflare.com. dns.cloudflare.com. 2397861234 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0