Apex domains cannot have CNAME records.
Question and response
Question
dig maur-mart.com. NS
Answer
maur-mart.com. 5 NS ns1.maur-mart.com.
maur-mart.com. 5 NS ns2.maur-mart.com.
Authority
The response has no authority records.
Additional
ns1.maur-mart.com. 5 A 81.17.132.130
ns2.maur-mart.com. 5 A 81.17.132.134
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0