Apex domains cannot have CNAME records.
Question and response
Question
dig publicaster.com. NS
Answer
publicaster.com. 2 NS ns-640.awsdns-16.net.
publicaster.com. 2 NS ns-1797.awsdns-32.co.uk.
publicaster.com. 2 NS ns-389.awsdns-48.com.
publicaster.com. 2 NS ns-1321.awsdns-37.org.
Authority
The response has no authority records.
Additional
ns-640.awsdns-16.net. 4 A 205.251.194.128
ns-1321.awsdns-37.org. 4 A 205.251.197.41
ns-1797.awsdns-32.co.uk. 4 A 205.251.199.5
ns-389.awsdns-48.com. 4 AAAA 2600:9000:5301:8500:0:0:0:1
ns-640.awsdns-16.net. 4 AAAA 2600:9000:5302:8000:0:0:0:1
ns-1321.awsdns-37.org. 4 AAAA 2600:9000:5305:2900:0:0:0:1
ns-1797.awsdns-32.co.uk. 4 AAAA 2600:9000:5307:500:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0