Apex domains cannot have CNAME records.
Question and response
Question
dig cmshigh.com. NS
Answer
cmshigh.com. 5 NS ns1.cmshigh.com.
cmshigh.com. 5 NS ns2.cmshigh.com.
Authority
The response has no authority records.
Additional
ns1.cmshigh.com. 5 A 86.107.32.33
ns2.cmshigh.com. 5 A 51.91.199.129
ns2.cmshigh.com. 5 A 86.107.36.23
ns2.cmshigh.com. 5 AAAA 2001:41d0:423:1a00:0:0:0:4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0