intersmtp.com CNAME records

CNAME Canonical name
Apex domains cannot have CNAME records.

Question and response

Question

dig intersmtp.com. NS

Answer

intersmtp.com. 5 NS ns2.bt.net. intersmtp.com. 5 NS ns1.bt.net. intersmtp.com. 5 NS ns0.bt.net.

Authority

The response has no authority records.

Additional

ns0.bt.net. 5 A 217.35.209.188 ns1.bt.net. 5 A 217.32.105.91 ns2.bt.net. 5 A 217.32.105.90 . 0 OPT ; payload 1232, xrcode 0, version 0, flags 0