Apex domains cannot have CNAME records.
Question and response
Question
dig decknet.com. NS
Answer
decknet.com. 5 NS ns2.decknet.com.
decknet.com. 5 NS ns1.decknet.com.
Authority
The response has no authority records.
Additional
ns1.decknet.com. 5 A 195.80.156.4
ns2.decknet.com. 5 A 195.80.157.4
ns1.decknet.com. 5 AAAA 2a00:1b11:115:10:195:80:156:4
ns2.decknet.com. 5 AAAA 2a00:1b11:116:11:195:80:157:4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0