Apex domains cannot have CNAME records.
Question and response
Question
dig spot.host. NS
Answer
spot.host. 5 NS ns2.spot.host.
spot.host. 5 NS ns3.spothost.nl.
spot.host. 5 NS ns1.spothost.eu.
Authority
The response has no authority records.
Additional
ns1.spothost.eu. 1 A 185.58.57.1
ns2.spot.host. 1 A 94.237.90.65
ns3.spothost.nl. 1 A 157.97.218.242
ns1.spothost.eu. 1 AAAA 2a01:310:8312:1046:185:58:57:1
ns2.spot.host. 1 AAAA 2a04:3542:1000:910:e0c3:50ff:feec:7ce7
ns3.spothost.nl. 1 AAAA 2a01:8580:2702:0:1009:0:242:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0