Apex domains cannot have CNAME records.
Question and response
Question
dig wtwco.com. NS
Answer
wtwco.com. 5 NS ha1.markmonitor.zone.
wtwco.com. 5 NS ha3.markmonitor.zone.
wtwco.com. 5 NS ha2.markmonitor.zone.
wtwco.com. 5 NS ha4.markmonitor.zone.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0