Apex domains cannot have CNAME records.
Question and response
Question
dig researchplannermail.com. NS
Answer
researchplannermail.com. 5 NS ns01.osl.basefarm.net.
researchplannermail.com. 5 NS ns01.sth.basefarm.net.
Authority
The response has no authority records.
Additional
ns01.osl.basefarm.net. 5 A 81.93.160.4
ns01.sth.basefarm.net. 5 A 80.76.149.76
ns01.osl.basefarm.net. 5 AAAA 2a01:600:1ffe:5:0:0:0:4
ns01.sth.basefarm.net. 5 AAAA 2a00:1d28:0:1:0:0:0:4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0