Apex domains cannot have CNAME records.
Question and response
Question
dig cdmon.com. NS
Answer
cdmon.com. 5 NS ns-1123.cdmon.com.
cdmon.com. 5 NS ns-635.cdmon.com.
cdmon.com. 5 NS ns-61.cdmon.com.
cdmon.com. 5 NS ns-1740.cdmon.com.
Authority
The response has no authority records.
Additional
ns-61.cdmon.com. 5 A 205.251.192.61
ns-635.cdmon.com. 5 A 205.251.194.123
ns-1123.cdmon.com. 5 A 205.251.196.99
ns-1740.cdmon.com. 5 A 205.251.198.204
ns-61.cdmon.com. 5 AAAA 2600:9000:5300:3d00:0:0:0:1
ns-635.cdmon.com. 5 AAAA 2600:9000:5302:7b00:0:0:0:1
ns-1123.cdmon.com. 5 AAAA 2600:9000:5304:6300:0:0:0:1
ns-1740.cdmon.com. 5 AAAA 2600:9000:5306:cc00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0