Apex domains cannot have CNAME records.
Question and response
Question
dig onebit.org. NS
Answer
onebit.org. 5 NS ns.onebit.eu.
onebit.org. 5 NS ns.onebit.org.
onebit.org. 5 NS ns.onebit.cz.
Authority
The response has no authority records.
Additional
ns.onebit.cz. 5 A 185.65.223.35
ns.onebit.eu. 5 A 217.31.48.201
ns.onebit.org. 5 A 178.62.60.201
ns.onebit.cz. 5 AAAA 2a00:1e40:a:53:0:0:0:5
ns.onebit.eu. 5 AAAA 2001:1ab0:7e1e:2:0:0:0:5
ns.onebit.org. 5 AAAA 2a03:b0c0:1:d0:0:0:1090:2001
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0