mx1.hostinger.com has no CNAME records.
Question and response
Question
dig mx1.hostinger.com. NS
Answer
The response has no answer records.
Authority
hostinger.com. 3341 SOA any1.hostinger.com. dns.hostinger.com. 2021102542 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0