Apex domains cannot have CNAME records.
Question and response
Question
dig surfsara.nl. NS
Answer
surfsara.nl. 5 NS ns3.surfnet.nl.
surfsara.nl. 5 NS ns2.surfnet.nl.
surfsara.nl. 5 NS ns1.zurich.surf.net.
surfsara.nl. 5 NS ns1.surfnet.nl.
surfsara.nl. 5 NS nsauth2.surfsara.nl.
surfsara.nl. 5 NS nsauth1.surfsara.nl.
Authority
The response has no authority records.
Additional
ns1.zurich.surf.net. 5 A 195.176.255.9
ns1.surfnet.nl. 5 A 192.87.106.101
ns2.surfnet.nl. 5 A 192.87.36.2
ns3.surfnet.nl. 5 A 195.169.124.71
nsauth1.surfsara.nl. 5 A 145.100.12.242
nsauth2.surfsara.nl. 5 A 145.100.12.243
ns1.zurich.surf.net. 5 AAAA 2001:620:0:9:0:0:0:1103
ns1.surfnet.nl. 5 AAAA 2001:610:1:800a:192:87:106:101
ns2.surfnet.nl. 5 AAAA 2001:610:3:200a:192:87:36:2
ns3.surfnet.nl. 5 AAAA 2001:610:0:800c:195:169:124:71
nsauth1.surfsara.nl. 5 AAAA 2001:610:108:2043:0:0:0:242
nsauth2.surfsara.nl. 5 AAAA 2001:610:108:2043:0:0:0:243
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0