Apex domains cannot have CNAME records.
Question and response
Question
dig nxtprod.careerbuilder.com. NS
Answer
nxtprod.careerbuilder.com. 1 NS ns-1113.awsdns-11.org.
nxtprod.careerbuilder.com. 1 NS ns-1972.awsdns-54.co.uk.
nxtprod.careerbuilder.com. 1 NS ns-206.awsdns-25.com.
nxtprod.careerbuilder.com. 1 NS ns-698.awsdns-23.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0