Apex domains cannot have CNAME records.
Question and response
Question
dig availo.com. NS
Answer
availo.com. 5 NS a.ns.ip-only.net.
availo.com. 5 NS c.ns.ip-only.net.
availo.com. 5 NS b.ns.ip-only.net.
Authority
The response has no authority records.
Additional
a.ns.ip-only.net. 5 A 212.112.160.42
b.ns.ip-only.net. 5 A 212.112.163.90
c.ns.ip-only.net. 5 A 83.145.7.217
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0