docker01.kustbandet.com has no CNAME records.
Question and response
Question
dig docker01.kustbandet.com. NS
Answer
The response has no answer records.
Authority
kustbandet.com. 9554 SOA ns01.kustbandet.com. hostmaster.kustbandet.com. 1179738999 10800 3600 1209600 38400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0