Apex domains cannot have CNAME records.
Question and response
Question
dig opsmta.tavant.com. NS
Answer
opsmta.tavant.com. 5 NS ns1.tavant.net.
Authority
The response has no authority records.
Additional
ns1.tavant.net. 4 A 165.193.250.82
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0