Apex domains cannot have CNAME records.
Question and response
Question
dig leaseweb.com. NS
Answer
leaseweb.com. 5 NS ns0.leaseweb.com.
leaseweb.com. 5 NS ns1.leaseweb.com.
Authority
The response has no authority records.
Additional
ns0.leaseweb.com. 5 A 23.19.196.53
ns1.leaseweb.com. 5 A 23.19.197.53
ns0.leaseweb.com. 5 AAAA 2607:f5b5:0:0:0:0:0:53
ns1.leaseweb.com. 5 AAAA 2607:f5b5:1:0:0:0:0:53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0