Apex domains cannot have CNAME records.
Question and response
Question
dig server.merithost50.com. NS
Answer
server.merithost50.com. 5 NS ns50.merithost50.com.
server.merithost50.com. 5 NS ns51.merithost50.com.
Authority
The response has no authority records.
Additional
ns50.merithost50.com. 5 A 158.69.54.61
ns51.merithost50.com. 5 A 158.69.54.61
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0