Apex domains cannot have CNAME records.
Question and response
Question
dig com.gt. NS
Answer
com.gt. 5 NS gt.anycastdns.cz.
com.gt. 5 NS a.lactld.org.
com.gt. 5 NS ssdns-tld.nic.cl.
com.gt. 5 NS gt-e.ns.nic.cz.
com.gt. 5 NS ns.dns.br.
com.gt. 5 NS pch.gt.
Authority
The response has no authority records.
Additional
a.lactld.org. 3 A 200.0.68.10
pch.gt. 95169 A 204.61.216.95
a.lactld.org. 3 AAAA 2801:14:a000:0:0:0:0:10
pch.gt. 95169 AAAA 2001:500:14:6095:ad:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0