Apex domains cannot have CNAME records.
Question and response
Question
dig mypetrojobs.com. NS
Answer
mypetrojobs.com. 5 NS ns1.mypetrojobs.com.
mypetrojobs.com. 5 NS ns2.mypetrojobs.com.
Authority
The response has no authority records.
Additional
ns1.mypetrojobs.com. 5 A 50.2.189.10
ns2.mypetrojobs.com. 5 A 50.2.125.38
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0