Apex domains cannot have CNAME records.
Question and response
Question
dig ns.ie. NS
Answer
ns.ie. 5 NS a.ns.ie.
ns.ie. 5 NS i.ns.ie.
ns.ie. 5 NS e.ns.ie.
ns.ie. 5 NS c.ns.ie.
Authority
The response has no authority records.
Additional
a.ns.ie. 122982 A 77.72.72.40
c.ns.ie. 122982 A 194.146.106.98
e.ns.ie. 122982 A 185.159.199.210
i.ns.ie. 122982 A 194.0.25.35
a.ns.ie. 122982 AAAA 2a01:4b0:0:0:0:0:0:40
c.ns.ie. 122982 AAAA 2001:67c:1010:25:0:0:0:53
e.ns.ie. 122982 AAAA 2620:10a:80ac:0:0:0:0:210
i.ns.ie. 122982 AAAA 2001:678:20:0:0:0:0:35
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0