Apex domains cannot have CNAME records.
Question and response
Question
dig trs-dns.info. NS
Answer
trs-dns.info. 1 NS ns02.trs-dns.com.
trs-dns.info. 1 NS ns02.trs-dns.net.
Authority
The response has no authority records.
Additional
ns02.trs-dns.com. 1 A 64.96.1.2
ns02.trs-dns.net. 1 A 64.96.2.2
ns02.trs-dns.com. 1 AAAA 2620:57:4001:0:0:0:0:2
ns02.trs-dns.net. 1 AAAA 2620:57:4002:0:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0