mx15.ncsdi.ws has no CNAME records.
Question and response
Question
dig mx15.ncsdi.ws. NS
Answer
The response has no answer records.
Authority
ncsdi.ws. 2380 SOA ns2.ncsdi.ws. hostmaster.ns2.ncsdi.ws. 2025041101 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0