Apex domains cannot have CNAME records.
Question and response
Question
dig infrassembly.com. NS
Answer
infrassembly.com. 5 NS ns1.zonomi.com.
infrassembly.com. 5 NS ns5.zonomi.com.
Authority
The response has no authority records.
Additional
ns5.zonomi.com. 2 A 178.62.131.147
ns5.zonomi.com. 2 AAAA 2a03:b0c0:0:1010:0:0:102:5001
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0