webserver.plumedns.com has no CNAME records.
Question and response
Question
dig webserver.plumedns.com. NS
Answer
The response has no answer records.
Authority
plumedns.com. 1824 SOA pns21.cloudns.net. support.cloudns.net. 2026020801 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0