mail.akku.email has no MX records.
Question and response
Question
dig mail.akku.email. MX
Answer
The response has no answer records.
Authority
akku.email. 1800 SOA curt.ns.cloudflare.com. dns.cloudflare.com. 2396392670 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0