Apex domains cannot have CNAME records.
Question and response
Question
dig pairserver.com. NS
Answer
pairserver.com. 2 NS ns1.pair.com.
pairserver.com. 2 NS ns0.ns0.com.
Authority
The response has no authority records.
Additional
ns0.ns0.com. 2 A 216.92.55.21
ns0.ns0.com. 2 AAAA 2607:f440:0:0:0:0:d85c:3715
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0