smtp2.spcnet.cz has no CNAME records.
Question and response
Question
dig smtp2.spcnet.cz. NS
Answer
The response has no answer records.
Authority
spcnet.cz. 3600 SOA ns.forpsi.net. admin.forpsi.com. 2026021702 14400 3600 2592000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0