Apex domains cannot have CNAME records.
Question and response
Question
dig preescolarpiaget.edu.do. NS
Answer
preescolarpiaget.edu.do. 5 NS ns74.domaincontrol.com.
preescolarpiaget.edu.do. 5 NS ns73.domaincontrol.com.
Authority
The response has no authority records.
Additional
ns73.domaincontrol.com. 3 A 97.74.106.47
ns74.domaincontrol.com. 3 A 173.201.74.47
ns73.domaincontrol.com. 3 AAAA 2603:5:21a4:0:0:0:0:2f
ns74.domaincontrol.com. 3 AAAA 2603:5:22a4:0:0:0:0:2f
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0