Apex domains cannot have CNAME records.
Question and response
Question
dig linktechs.email. NS
Answer
linktechs.email. 5 NS ns1.linktechs.net.
linktechs.email. 5 NS ns2.linktechs.net.
Authority
The response has no authority records.
Additional
ns1.linktechs.net. 5 A 139.60.210.20
ns2.linktechs.net. 5 A 139.60.210.21
ns1.linktechs.net. 5 AAAA 2620:13c:b000:0:0:0:0:20
ns2.linktechs.net. 5 AAAA 2620:13c:b000:0:0:0:0:21
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0