ns4.mixarthost.com has no CNAME records.
Question and response
Question
dig ns4.mixarthost.com. NS
Answer
The response has no answer records.
Authority
mixarthost.com. 10800 SOA ns3.mixarthost.com. info.dominet.net. 2026030300 3600 7200 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0