Apex domains cannot have CNAME records.
Question and response
Question
dig crowdtech.com. NS
Answer
crowdtech.com. 1 NS ns-n.dns.yourhosting.eu.
crowdtech.com. 1 NS ns-c.dns.yourhosting.nu.
crowdtech.com. 1 NS ns-s.dns.yourhosting.nl.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0