kiki.bunny.net has no MX records.
Question and response
Question
dig kiki.bunny.net. MX
Answer
The response has no answer records.
Authority
bunny.net. 900 SOA kiki.bunny.net. hostmaster.bunny.net. 2021696340 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0