mail.mydnsservice.com has no CNAME records.
Question and response
Question
dig mail.mydnsservice.com. NS
Answer
The response has no answer records.
Authority
mydnsservice.com. 6551 SOA admi292808.mercury.orderbox-dns.com. support.databasemart.com. 2024092602 7200 7200 172800 38400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0