Apex domains cannot have CNAME records.
Question and response
Question
dig questback.net. NS
Answer
questback.net. 5 NS ns2.dnshost.net.
questback.net. 5 NS ns1.dnshost.net.
Authority
The response has no authority records.
Additional
ns1.dnshost.net. 5 A 91.237.67.1
ns2.dnshost.net. 5 A 185.167.176.1
ns1.dnshost.net. 5 AAAA 2a0b:8e00:0:0:0:0:0:10
ns2.dnshost.net. 5 AAAA 2a0b:8e00:1:0:0:0:0:10
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0