Apex domains cannot have CNAME records.
Question and response
Question
dig blazing.de. NS
Answer
blazing.de. 1 NS ns3.waaf.net.
blazing.de. 1 NS ns2.blazing.de.
blazing.de. 1 NS ns1.blazing.de.
blazing.de. 1 NS ns1.cyconet.org.
Authority
The response has no authority records.
Additional
ns1.blazing.de. 1 A 213.172.105.106
ns1.cyconet.org. 1 A 217.145.103.249
ns3.waaf.net. 1 A 188.166.73.66
ns1.blazing.de. 1 AAAA 2001:1640:3:0:0:0:0:53
ns1.cyconet.org. 1 AAAA 2001:4dc8:9000:1500:0:0:0:53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0