Apex domains cannot have CNAME records.
Question and response
Question
dig nsone.m-wifo.com. NS
Answer
nsone.m-wifo.com. 5 NS ns2.m-wifo.com.
nsone.m-wifo.com. 5 NS ns1.m-wifo.com.
Authority
The response has no authority records.
Additional
ns1.m-wifo.com. 4 A 202.51.96.18
ns2.m-wifo.com. 4 A 202.51.104.7
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0