Apex domains cannot have CNAME records.
Question and response
Question
dig a2webhosting.com. NS
Answer
a2webhosting.com. 5 NS a2ns2.a2hosting.com.
a2webhosting.com. 5 NS a2ns1.a2hosting.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0