Apex domains cannot have CNAME records.
Question and response
Question
dig hulpsystems.net. NS
Answer
hulpsystems.net. 4 NS ns.ger.airwire.ie.
hulpsystems.net. 4 NS ns.gal.airwire.ie.
hulpsystems.net. 4 NS ns.dub.airwire.ie.
Authority
The response has no authority records.
Additional
ns.dub.airwire.ie. 4 A 91.189.64.189
ns.gal.airwire.ie. 4 A 195.222.111.222
ns.ger.airwire.ie. 4 A 80.190.248.146
ns.dub.airwire.ie. 4 AAAA 2a02:278:0:0:0:0:0:1
ns.gal.airwire.ie. 4 AAAA 2a02:278:50:0:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0