mailgate01.rednet.ch has no CNAME records.
Question and response
Question
dig mailgate01.rednet.ch. NS
Answer
The response has no answer records.
Authority
rednet.ch. 3335 SOA customerdns001.redcloud.ch. rednet.ch. 2026012001 86400 7200 3600000 172800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0