Apex domains cannot have CNAME records.
Question and response
Question
dig rlb.com. NS
Answer
rlb.com. 5 NS ns6.netnames.net.
rlb.com. 5 NS ns7.netnames.net.
rlb.com. 5 NS ns8.netnames.net.
rlb.com. 5 NS ns1.netnames.net.
rlb.com. 5 NS ns5.netnames.net.
rlb.com. 5 NS ns2.netnames.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0