Apex domains cannot have CNAME records.
Question and response
Question
dig cristal-agency.com. NS
Answer
cristal-agency.com. 4 NS ns-472.awsdns-59.com.
cristal-agency.com. 4 NS ns-407.awsdns-50.com.
cristal-agency.com. 4 NS ns-231.awsdns-28.com.
cristal-agency.com. 4 NS ns-1824.awsdns-36.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0