Apex domains cannot have CNAME records.
Question and response
Question
dig twdcns.info. NS
Answer
twdcns.info. 5 NS ns6.twdcns.co.uk.
twdcns.info. 5 NS ns1.twdcns.com.
twdcns.info. 5 NS ns2.twdcns.com.
twdcns.info. 5 NS ns3.twdcns.info.
twdcns.info. 5 NS ns4.twdcns.info.
twdcns.info. 5 NS ns5.twdcns.co.uk.
Authority
The response has no authority records.
Additional
ns3.twdcns.info. 5 A 95.100.173.64
ns4.twdcns.info. 5 A 204.74.110.147
ns4.twdcns.info. 5 AAAA 2610:a1:1014:0:0:0:0:293
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0