Apex domains cannot have CNAME records.
Question and response
Question
dig voip.ms. NS
Answer
voip.ms. 5 NS chan.ns.cloudflare.com.
voip.ms. 5 NS langston.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0