smtp.thegoodcloud.net has no CNAME records.
Question and response
Question
dig smtp.thegoodcloud.net. NS
Answer
The response has no answer records.
Authority
thegoodcloud.net. 300 SOA auth01.dns.trueserver.nl. hostmaster.trueserver.nl. 2025071603 86400 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0