mx1.cpanel.net has no MX records.
Question and response
Question
dig mx1.cpanel.net. MX
Answer
The response has no answer records.
Authority
cpanel.net. 300 SOA c.cpanel.net. dns.cpanel.net. 2026030912 1200 7200 1600000 300
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0