Apex domains cannot have CNAME records.
Question and response
Question
dig eprism-cloud.net. NS
Answer
eprism-cloud.net. 5 NS ns-1574.awsdns-04.co.uk.
eprism-cloud.net. 5 NS ns-205.awsdns-25.com.
eprism-cloud.net. 5 NS ns-775.awsdns-32.net.
eprism-cloud.net. 5 NS ns-1149.awsdns-15.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0