Apex domains cannot have CNAME records.
Question and response
Question
dig iberlayer.com. NS
Answer
iberlayer.com. 2 NS makemake.iberlayer.com.
iberlayer.com. 2 NS ixion.iberlayer.com.
iberlayer.com. 2 NS dismonia.iberlayer.com.
Authority
The response has no authority records.
Additional
ixion.iberlayer.com. 2 A 185.136.219.29
dismonia.iberlayer.com. 2 A 80.169.225.50
makemake.iberlayer.com. 2 A 130.117.89.19
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0