mx1.schoolsource.io has no CNAME records.
Question and response
Question
dig mx1.schoolsource.io. NS
Answer
The response has no answer records.
Authority
schoolsource.io. 504 SOA ns1.dns-parking.com. dns.hostinger.com. 2026021901 10000 2400 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0