Apex domains cannot have CNAME records.
Question and response
Question
dig main-hosting.eu. NS
Answer
main-hosting.eu. 5 NS any1.hostinger.com.
main-hosting.eu. 5 NS any2.hostinger.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0