Apex domains cannot have CNAME records.
Question and response
Question
dig spamexperts.NET. NS
Answer
spamexperts.NET. 1 NS ns-384.awsdns-48.com.
spamexperts.NET. 1 NS ns-619.awsdns-13.NET.
spamexperts.NET. 1 NS ns-1071.awsdns-05.org.
spamexperts.NET. 1 NS ns-1997.awsdns-57.co.uk.
Authority
The response has no authority records.
Additional
ns-384.awsdns-48.com. 1 A 205.251.193.128
ns-1071.awsdns-05.org. 1 A 205.251.196.47
ns-1997.awsdns-57.co.uk. 1 A 205.251.199.205
ns-384.awsdns-48.com. 1 AAAA 2600:9000:5301:8000:0:0:0:1
ns-619.awsdns-13.net. 1 AAAA 2600:9000:5302:6b00:0:0:0:1
ns-1071.awsdns-05.org. 1 AAAA 2600:9000:5304:2f00:0:0:0:1
ns-1997.awsdns-57.co.uk. 1 AAAA 2600:9000:5307:cd00:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0