Apex domains cannot have CNAME records.
Question and response
Question
dig cr. NS
Answer
cr. 5 NS dns.nic.cr.
cr. 5 NS a.lactld.org.
cr. 5 NS p.nic.cr.
cr. 5 NS de.nic.cr.
cr. 5 NS ca1.nic.cr.
cr. 5 NS ca2.nic.cr.
Authority
The response has no authority records.
Additional
a.lactld.org. 5 A 200.0.68.10
p.nic.cr. 143240 A 204.61.216.89
de.nic.cr. 137495 A 194.0.11.107
ca1.nic.cr. 137495 A 185.159.197.100
ca2.nic.cr. 137495 A 185.159.198.100
dns.nic.cr. 88844 A 200.107.82.100
a.lactld.org. 5 AAAA 2801:14:a000:0:0:0:0:10
p.nic.cr. 143240 AAAA 2001:500:14:6089:ad:0:0:1
de.nic.cr. 137495 AAAA 2001:678:e:107:0:0:0:53
ca1.nic.cr. 137495 AAAA 2620:10a:80aa:0:0:0:0:100
ca2.nic.cr. 137495 AAAA 2620:10a:80ab:0:0:0:0:100
dns.nic.cr. 88844 AAAA 2001:13c7:7004:1:0:0:0:d100
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0