Apex domains cannot have CNAME records.
Question and response
Question
dig megabit.at. NS
Answer
megabit.at. 5 NS a.ns.keyweb.org.
megabit.at. 5 NS c.ns.keyweb.de.
megabit.at. 5 NS b.ns.keyweb.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0