mx1.jellyfish.systems has no CNAME records.
Question and response
Question
dig mx1.jellyfish.systems. NS
Answer
The response has no answer records.
Authority
jellyfish.systems. 2933 SOA edns.registrar-servers.com. hostmaster.registrar-servers.com. 1770826720 43200 3600 604800 3601
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0