Apex domains cannot have CNAME records.
Question and response
Question
dig allianz.com. NS
Answer
allianz.com. 2 NS ns5.az-ip.net.
allianz.com. 2 NS ns3.allianz.de.
allianz.com. 2 NS ns2.allianz.com.
allianz.com. 2 NS ns1.allianz.com.
allianz.com. 2 NS ns4.allianz.de.
allianz.com. 2 NS ns6.az-ip.net.
Authority
The response has no authority records.
Additional
ns1.allianz.com. 2 A 194.127.26.151
ns2.allianz.com. 2 A 195.253.114.7
ns3.allianz.de. 2 A 194.127.24.151
ns4.allianz.de. 2 A 195.253.116.8
ns5.az-ip.net. 2 A 205.167.40.147
ns6.az-ip.net. 2 A 195.253.118.9
ns2.allianz.com. 2 AAAA 2a01:5b0:32:0:0:0:0:7
ns3.allianz.de. 2 AAAA 2a01:6f8:2004:f0be:0:0:1:53
ns4.allianz.de. 2 AAAA 2a01:5b0:34:0:0:0:0:8
ns6.az-ip.net. 2 AAAA 2a01:5b0:36:0:0:0:0:9
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0