ns4.dnsever.co.uk has no CNAME records.
Question and response
Question
dig ns4.dnsever.co.uk. NS
Answer
The response has no answer records.
Authority
dnsever.co.uk. 10800 SOA ns3.dnsever.co.uk. admin.dnsever.com. 1742891024 86400 600 1209600 14400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0