Apex domains cannot have CNAME records.
Question and response
Question
dig esendex.com. NS
Answer
esendex.com. 5 NS ns-d.eurodns.biz.
esendex.com. 5 NS ns-a.eurodns.com.
esendex.com. 5 NS ns-b.eurodns.org.
esendex.com. 5 NS ns-c.eurodns.eu.
Authority
The response has no authority records.
Additional
ns-a.eurodns.com. 5 A 199.167.66.106
ns-b.eurodns.org. 5 A 104.37.178.106
ns-c.eurodns.eu. 5 A 192.174.68.110
ns-a.eurodns.com. 5 AAAA 2610:1c8:b002:0:0:0:0:106
ns-b.eurodns.org. 5 AAAA 2610:1c8:b001:0:0:0:0:106
ns-c.eurodns.eu. 5 AAAA 2001:67c:1bc:0:0:0:0:110
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0