Apex domains cannot have CNAME records.
Question and response
Question
dig selcoroofingandsiding.com. NS
Answer
selcoroofingandsiding.com. 5 NS ns1.selcoroofingandsiding.com.
selcoroofingandsiding.com. 5 NS ns2.selcoroofingandsiding.com.
Authority
The response has no authority records.
Additional
ns1.selcoroofingandsiding.com. 5 A 216.106.180.115
ns2.selcoroofingandsiding.com. 5 A 216.106.180.20
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0