Apex domains cannot have CNAME records.
Question and response
Question
dig se-filter05.mta.whmpanels.com. NS
Answer
se-filter05.mta.whmpanels.com. 5 NS ns2.romarg.com.
se-filter05.mta.whmpanels.com. 5 NS ns4.romarg.com.
se-filter05.mta.whmpanels.com. 5 NS ns1.romarg.com.
se-filter05.mta.whmpanels.com. 5 NS ns3.romarg.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0