Apex domains cannot have CNAME records.
Question and response
Question
dig ns5.brdrive.net. NS
Answer
ns5.brdrive.net. 5 NS ns5.brdrive.net.
ns5.brdrive.net. 5 NS ns4.brdrive.net.
Authority
The response has no authority records.
Additional
ns4.brdrive.net. 5 A 45.163.12.10
ns5.brdrive.net. 5 A 45.163.15.10
ns4.brdrive.net. 5 AAAA 2804:5384:1:10:0:0:0:10
ns5.brdrive.net. 5 AAAA 2804:5384:302:10:45:163:15:10
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0