frontend01.mailsafe.dk has no CNAME records.
Question and response
Question
dig frontend01.mailsafe.dk. NS
Answer
The response has no answer records.
Authority
mailsafe.dk. 35 SOA ns001.dnspilot.com. hostmaster.dnspilot.com. 2016050310 14400 7200 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0