_spf.onebit.cz has no CNAME records.
Question and response
Question
dig _spf.onebit.cz. NS
Answer
The response has no answer records.
Authority
onebit.cz. 3086 SOA ns.onebit.cz. hostmaster.onebit.cz. 2026021601 43200 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0