Apex domains cannot have CNAME records.
Question and response
Question
dig mgn.net. NS
Answer
mgn.net. 5 NS ns-1309.awsdns-35.org.
mgn.net. 5 NS ns-841.awsdns-41.net.
mgn.net. 5 NS ns-143.awsdns-17.com.
mgn.net. 5 NS ns-1738.awsdns-25.co.uk.
Authority
The response has no authority records.
Additional
ns-143.awsdns-17.com. 1 A 205.251.192.143
ns-1309.awsdns-35.org. 1 A 205.251.197.29
ns-1738.awsdns-25.co.uk. 1 A 205.251.198.202
ns-143.awsdns-17.com. 1 AAAA 2600:9000:5300:8f00:0:0:0:1
ns-841.awsdns-41.net. 1 AAAA 2600:9000:5303:4900:0:0:0:1
ns-1309.awsdns-35.org. 1 AAAA 2600:9000:5305:1d00:0:0:0:1
ns-1738.awsdns-25.co.uk. 1 AAAA 2600:9000:5306:ca00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0