Apex domains cannot have CNAME records.
Question and response
Question
dig gmoregistry.net. NS
Answer
gmoregistry.net. 5 NS bdns03.gmoregistry.net.
gmoregistry.net. 5 NS bdns02.gmoregistry.net.
gmoregistry.net. 5 NS bdns01.gmoregistry.net.
Authority
The response has no authority records.
Additional
bdns01.gmoregistry.net. 5 A 208.94.148.13
bdns02.gmoregistry.net. 5 A 208.80.124.13
bdns03.gmoregistry.net. 5 A 208.80.126.13
bdns01.gmoregistry.net. 5 AAAA 2600:1800:5:0:0:0:0:1
bdns02.gmoregistry.net. 5 AAAA 2600:1801:6:0:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0