Apex domains cannot have CNAME records.
Question and response
Question
dig kss.edu.do. NS
Answer
kss.edu.do. 1 NS ns1.linode.com.
kss.edu.do. 1 NS ns3.linode.com.
kss.edu.do. 1 NS ns5.linode.com.
kss.edu.do. 1 NS ns2.linode.com.
kss.edu.do. 1 NS ns4.linode.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0