Apex domains cannot have CNAME records.
Question and response
Question
dig tm-4.office.com. NS
Answer
tm-4.office.com. 5 NS ns2.tm-4.office.com.
tm-4.office.com. 5 NS ns1.tm-4.office.com.
tm-4.office.com. 5 NS ns4.tm-4.office.com.
tm-4.office.com. 5 NS ns3.tm-4.office.com.
Authority
The response has no authority records.
Additional
ns1.tm-4.office.com. 5 A 150.171.10.34
ns2.tm-4.office.com. 5 A 150.171.16.34
ns3.tm-4.office.com. 5 A 13.107.222.34
ns4.tm-4.office.com. 5 A 13.107.206.34
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0