portal.plus.net has no CNAME records.
Question and response
Question
dig portal.plus.net. NS
Answer
The response has no answer records.
Authority
plus.net. 10800 SOA ns1.force9.net. hostmaster.plus.net.uk. 2026030501 43200 1800 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0