mx1.tld-mx.com has no CNAME records.
Question and response
Question
dig mx1.tld-mx.com. NS
Answer
The response has no answer records.
Authority
tld-mx.com. 761 SOA ns1.tld-nscloud.com. support.cloudns.net. 2026021901 7200 1800 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0