Apex domains cannot have CNAME records.
Question and response
Question
dig mpssec.net. NS
Answer
mpssec.net. 5 NS ns12.mpssec.net.
mpssec.net. 5 NS ns13.mpssec.net.
mpssec.net. 5 NS ns11.mpssec.net.
Authority
The response has no authority records.
Additional
ns11.mpssec.net. 5 A 185.175.91.11
ns12.mpssec.net. 5 A 185.175.91.12
ns13.mpssec.net. 5 A 185.175.91.13
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0