mx4.hin.ch has no CNAME records.
Question and response
Question
dig mx4.hin.ch. NS
Answer
The response has no answer records.
Authority
hin.ch. 746 SOA ns-1774.awsdns-29.co.uk. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0