Apex domains cannot have CNAME records.
Question and response
Question
dig phg.systems. NS
Answer
phg.systems. 5 NS dns2.gestiondeservidor.com.
phg.systems. 5 NS dns1.gestiondeservidor.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0