Apex domains cannot have CNAME records.
Question and response
Question
dig ae. NS
Answer
ae. 5 NS ns4.apnic.net.
ae. 5 NS ns1.aedns.ae.
ae. 5 NS ns2.aedns.ae.
ae. 5 NS nsext-pch.aedns.ae.
Authority
The response has no authority records.
Additional
ns1.aedns.ae. 84725 A 79.98.120.73
ns2.aedns.ae. 84725 A 79.98.121.73
ns4.apnic.net. 2 A 202.12.31.53
nsext-pch.aedns.ae. 167729 A 199.4.137.1
ns1.aedns.ae. 84725 AAAA 2a00:d30:120:0:0:0:0:73
ns2.aedns.ae. 84725 AAAA 2a00:d30:121:0:0:0:0:73
ns4.apnic.net. 2 AAAA 2001:dd8:12:0:0:0:0:53
nsext-pch.aedns.ae. 167729 AAAA 2001:500:7d:0:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0