Apex domains cannot have CNAME records.
Question and response
Question
dig rugbymags.com. NS
Answer
rugbymags.com. 1 NS ns1.rugbymags.com.
rugbymags.com. 1 NS ns2.rugbymags.com.
Authority
The response has no authority records.
Additional
ns1.rugbymags.com. 1 A 69.167.168.43
ns2.rugbymags.com. 1 A 67.225.249.71
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0