Apex domains cannot have CNAME records.
Question and response
Question
dig mtbtoledo.com. NS
Answer
mtbtoledo.com. 5 NS ns2.mtbtoledo.com.
mtbtoledo.com. 5 NS ns1.mtbtoledo.com.
Authority
The response has no authority records.
Additional
ns1.mtbtoledo.com. 5 A 54.37.82.2
ns2.mtbtoledo.com. 5 A 5.135.31.122
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0