Apex domains cannot have CNAME records.
Question and response
Question
dig iowashorthorn.com. NS
Answer
iowashorthorn.com. 5 NS ns1.iowashorthorn.com.
iowashorthorn.com. 5 NS ns2.iowashorthorn.com.
Authority
The response has no authority records.
Additional
ns1.iowashorthorn.com. 5 A 142.44.136.25
ns2.iowashorthorn.com. 5 A 51.222.0.4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0